BASELINE: Update Chromium to 79.0.3945.139

Change-Id: I336b7182fab9bca80b709682489c07db112eaca5
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

48 files changed, 1614 insertions, 1278 deletions

diff --git a/chromium/chrome/browser/resources/pdf/BUILD.gn b/chromium/chrome/browser/resources/pdf/BUILD.gn
index 89a0223ca86..079381842d8 100644
--- a/chromium/chrome/browser/resources/pdf/BUILD.gn
+++ b/chromium/chrome/browser/resources/pdf/BUILD.gn
@@ -4,28 +4,19 @@
 
 import("//third_party/closure_compiler/compile_js.gni")
 
-# TODO(dpapad): Add compile targets for all files, crbug.com/721073.
 group("closure_compile") {
   deps = [
     ":pdf_resources",
-    "elements/viewer-bookmark:closure_compile",
-    "elements/viewer-error-screen:closure_compile",
-    "elements/viewer-form-warning:closure_compile",
-    "elements/viewer-page-indicator:closure_compile",
-    "elements/viewer-page-selector:closure_compile",
-    "elements/viewer-password-screen:closure_compile",
-    "elements/viewer-pdf-toolbar:closure_compile",
-    "elements/viewer-toolbar-dropdown:closure_compile",
-    "elements/viewer-zoom-toolbar:closure_compile",
+    "elements:closure_compile",
   ]
   if (is_chromeos) {
-    deps += [
-      "elements/viewer-ink-host:closure_compile",
-      "ink:closure_compile",
-    ]
+    deps += [ "ink:closure_compile" ]
   }
 }
 
+js_library("annotation_tool") {
+}
+
 js_library("browser_api") {
   deps = [
     "//ui/webui/resources/js:assert",
@@ -86,15 +77,53 @@ js_library("navigator") {
   ]
 }
 
+js_library("toolbar_manager") {
+  deps = [
+    "elements:viewer-pdf-toolbar",
+    "elements:viewer-zoom-toolbar",
+  ]
+}
+
+js_library("controller") {
+  deps = [
+    ":annotation_tool",
+    ":viewport",
+    "elements:viewer-pdf-toolbar",
+    "//ui/webui/resources/js:load_time_data",
+    "//ui/webui/resources/js/cr:event_target",
+  ]
+}
+
+js_library("pdf_viewer") {
+  deps = [
+    ":controller",
+    ":navigator",
+    ":toolbar_manager",
+    ":viewport",
+    "elements:viewer-bookmark",
+    "elements:viewer-error-screen",
+    "elements:viewer-page-indicator",
+    "elements:viewer-password-screen",
+    "elements:viewer-pdf-toolbar",
+    "elements:viewer-zoom-toolbar",
+    "//ui/webui/resources/js:event_tracker",
+    "//ui/webui/resources/js:load_time_data",
+  ]
+  externs_list = [ "$externs_path/resources_private.js" ]
+}
+
 js_type_check("pdf_resources") {
   deps = [
     ":browser_api",
+    ":controller",
     ":gesture_detector",
     ":metrics",
     ":navigator",
     ":open_pdf_params_parser",
     ":pdf_fitting_type",
     ":pdf_scripting_api",
+    ":pdf_viewer",
+    ":toolbar_manager",
     ":viewport",
     ":viewport_scroller",
     ":zoom_manager",
diff --git a/chromium/chrome/browser/resources/pdf/annotation_tool.js b/chromium/chrome/browser/resources/pdf/annotation_tool.js
new file mode 100644
index 00000000000..5e887b048b7
--- /dev/null
+++ b/chromium/chrome/browser/resources/pdf/annotation_tool.js
@@ -0,0 +1,15 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// @fileoverview This file is not included in the build. Only used for type
+// checking purposes.
+
+/**
+ * @typedef {{
+ *   tool: string,
+ *   size: number,
+ *   color: (string|null),
+ * }}
+ */
+let AnnotationTool;
diff --git a/chromium/chrome/browser/resources/pdf/controller.js b/chromium/chrome/browser/resources/pdf/controller.js
new file mode 100644
index 00000000000..ea790f32d0f
--- /dev/null
+++ b/chromium/chrome/browser/resources/pdf/controller.js
@@ -0,0 +1,494 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+'use strict';
+
+/** @typedef {{ type: string }} */
+let MessageData;
+
+/**
+ * @typedef {{
+ *   dataToSave: Array,
+ *   token: string,
+ *   fileName: string
+ * }}
+ */
+let SaveDataMessageData;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   to: string,
+ *   cc: string,
+ *   bcc: string,
+ *   subject: string,
+ *   body: string,
+ * }}
+ */
+let EmailMessageData;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   url: string,
+ *   grayscale: boolean,
+ *   modifiable: boolean,
+ *   pageNumbers: !Array<number>
+ * }}
+ */
+let PrintPreviewParams;
+
+// Note: Redefining this type here, to work around the fact that ink externs
+// are only available on Chrome OS, so the targets that contain them cannot be
+// built on other platforms.
+// TODO (rbpotter): Break InkController into its own file that is only included
+// on Chrome OS.
+
+/**
+ * @typedef {{
+ *   setAnnotationTool: function(AnnotationTool):void,
+ *   viewportChanged: function():void,
+ *   saveDocument: function():!Promise,
+ *   undo: function():void,
+ *   redo: function():void,
+ *   load: function(string, !ArrayBuffer):!Promise,
+ *   viewport: !Viewport,
+ * }}
+ */
+let ViewerInkHostElement;
+
+/**
+ * Creates a cryptographically secure pseudorandom 128-bit token.
+ * @return {string} The generated token as a hex string.
+ */
+function createToken() {
+  const randomBytes = new Uint8Array(16);
+  return window.crypto.getRandomValues(randomBytes)
+      .map(b => b.toString(16).padStart(2, '0'))
+      .join('');
+}
+
+/** @abstract */
+class ContentController {
+  constructor() {}
+
+  beforeZoom() {}
+
+  afterZoom() {}
+
+  viewportChanged() {}
+
+  /** @abstract */
+  rotateClockwise() {}
+
+  /** @abstract */
+  rotateCounterclockwise() {}
+
+  /** Triggers printing of the current document. */
+  print() {}
+
+  /** Undo an edit action. */
+  undo() {}
+
+  /** Redo an edit action. */
+  redo() {}
+
+  /**
+   * Requests that the current document be saved.
+   * @param {boolean} requireResult whether a response is required, otherwise
+   *     the controller may save the document to disk internally.
+   * @return {Promise<{fileName: string, dataToSave: ArrayBuffer}>}
+   * @abstract
+   */
+  save(requireResult) {}
+
+  /**
+   * Loads PDF document from `data` activates UI.
+   * @param {string} fileName
+   * @param {!ArrayBuffer} data
+   * @return {Promise<void>}
+   * @abstract
+   */
+  load(fileName, data) {}
+
+  /**
+   * Unloads the current document and removes the UI.
+   * @abstract
+   */
+  unload() {}
+}
+
+/**
+ * Controller for annotation mode, on Chrome OS only. Fires the following events
+ * from its event target:
+ * has-unsaved-changes: Fired to indicate there are ink annotations that have
+ *     not been saved.
+ * set-annotation-undo-state: Contains information about whether undo or redo
+ *     options are available.
+ */
+class InkController extends ContentController {
+  /** @param {!Viewport} viewport */
+  constructor(viewport) {
+    super();
+
+    /** @private {!Viewport} */
+    this.viewport_ = viewport;
+
+    /** @private {?ViewerInkHostElement} */
+    this.inkHost_ = null;
+
+    /** @private {!EventTarget} */
+    this.eventTarget_ = new cr.EventTarget();
+
+    /** @type {?AnnotationTool} */
+    this.tool_ = null;
+  }
+
+  /** @return {!EventTarget} */
+  getEventTarget() {
+    return this.eventTarget_;
+  }
+
+  /** @param {AnnotationTool} tool */
+  setAnnotationTool(tool) {
+    this.tool_ = tool;
+    if (this.inkHost_) {
+      this.inkHost_.setAnnotationTool(tool);
+    }
+  }
+
+  /** @override */
+  rotateClockwise() {
+    // TODO(dstockwell): implement rotation
+  }
+
+  /** @override */
+  rotateCounterclockwise() {
+    // TODO(dstockwell): implement rotation
+  }
+
+  /** @override */
+  viewportChanged() {
+    this.inkHost_.viewportChanged();
+  }
+
+  /** @override */
+  save(requireResult) {
+    return this.inkHost_.saveDocument();
+  }
+
+  /** @override */
+  undo() {
+    this.inkHost_.undo();
+  }
+
+  /** @override */
+  redo() {
+    this.inkHost_.redo();
+  }
+
+  /** @override */
+  load(filename, data) {
+    if (!this.inkHost_) {
+      const inkHost = document.createElement('viewer-ink-host');
+      $('content').appendChild(inkHost);
+      this.inkHost_ = /** @type {!ViewerInkHostElement} */ (inkHost);
+      this.inkHost_.viewport = this.viewport_;
+      inkHost.addEventListener('stroke-added', e => {
+        this.eventTarget_.dispatchEvent(new CustomEvent('has-unsaved-changes'));
+      });
+      inkHost.addEventListener('undo-state-changed', e => {
+        this.eventTarget_.dispatchEvent(
+            new CustomEvent('set-annotation-undo-state', {detail: e.detail}));
+      });
+    }
+    return this.inkHost_.load(filename, data);
+  }
+
+  /** @override */
+  unload() {
+    this.inkHost_.remove();
+    this.inkHost_ = null;
+  }
+}
+
+/**
+ * PDF plugin controller, responsible for communicating with the embedded plugin
+ * element. Dispatches a 'plugin-message' event containing the message from the
+ * plugin, if a message type not handled by this controller is received.
+ */
+class PluginController extends ContentController {
+  /**
+   * @param {!HTMLEmbedElement} plugin
+   * @param {!Viewport} viewport
+   * @param {function():boolean} getIsUserInitiatedCallback
+   * @param {function():?Promise} getLoadedCallback
+   */
+  constructor(plugin, viewport, getIsUserInitiatedCallback, getLoadedCallback) {
+    super();
+
+    /** @private {!HTMLEmbedElement} */
+    this.plugin_ = plugin;
+
+    /** @private {!Viewport} */
+    this.viewport_ = viewport;
+
+    /** @private {!function():boolean} */
+    this.getIsUserInitiatedCallback_ = getIsUserInitiatedCallback;
+
+    /** @private {!function():?Promise} */
+    this.getLoadedCallback_ = getLoadedCallback;
+
+    /** @private {!Map<string, PromiseResolver>} */
+    this.pendingTokens_ = new Map();
+    this.plugin_.addEventListener(
+        'message', e => this.handlePluginMessage_(e), false);
+
+    /** @private {!EventTarget} */
+    this.eventTarget_ = new cr.EventTarget();
+  }
+
+  /** @return {!EventTarget} */
+  getEventTarget() {
+    return this.eventTarget_;
+  }
+
+  /**
+   * Notify the plugin to stop reacting to scroll events while zoom is taking
+   * place to avoid flickering.
+   * @override
+   */
+  beforeZoom() {
+    this.postMessage_({type: 'stopScrolling'});
+
+    if (this.viewport_.pinchPhase == Viewport.PinchPhase.PINCH_START) {
+      const position = this.viewport_.position;
+      const zoom = this.viewport_.getZoom();
+      const pinchPhase = this.viewport_.pinchPhase;
+      const layoutOptions = this.viewport_.getLayoutOptions();
+      this.postMessage_({
+        type: 'viewport',
+        userInitiated: true,
+        zoom: zoom,
+        layoutOptions: layoutOptions,
+        xOffset: position.x,
+        yOffset: position.y,
+        pinchPhase: pinchPhase
+      });
+    }
+  }
+
+  /**
+   * Notify the plugin of the zoom change and to continue reacting to scroll
+   * events.
+   * @override
+   */
+  afterZoom() {
+    const position = this.viewport_.position;
+    const zoom = this.viewport_.getZoom();
+    const layoutOptions = this.viewport_.getLayoutOptions();
+    const pinchVector = this.viewport_.pinchPanVector || {x: 0, y: 0};
+    const pinchCenter = this.viewport_.pinchCenter || {x: 0, y: 0};
+    const pinchPhase = this.viewport_.pinchPhase;
+
+    this.postMessage_({
+      type: 'viewport',
+      userInitiated: this.getIsUserInitiatedCallback_(),
+      zoom: zoom,
+      layoutOptions: layoutOptions,
+      xOffset: position.x,
+      yOffset: position.y,
+      pinchPhase: pinchPhase,
+      pinchX: pinchCenter.x,
+      pinchY: pinchCenter.y,
+      pinchVectorX: pinchVector.x,
+      pinchVectorY: pinchVector.y
+    });
+  }
+
+  /**
+   * Post a message to the PPAPI plugin. Some messages will cause an async reply
+   * to be received through handlePluginMessage_().
+   * @param {!MessageData} message Message to post.
+   * @private
+   */
+  postMessage_(message) {
+    this.plugin_.postMessage(message);
+  }
+
+  /** @override */
+  rotateClockwise() {
+    this.postMessage_({type: 'rotateClockwise'});
+  }
+
+  /** @override */
+  rotateCounterclockwise() {
+    this.postMessage_({type: 'rotateCounterclockwise'});
+  }
+
+  /** @override */
+  print() {
+    this.postMessage_({type: 'print'});
+  }
+
+  selectAll() {
+    this.postMessage_({type: 'selectAll'});
+  }
+
+  getSelectedText() {
+    this.postMessage_({type: 'getSelectedText'});
+  }
+
+  /** @param {!PrintPreviewParams} printPreviewParams */
+  resetPrintPreviewMode(printPreviewParams) {
+    this.postMessage_({
+      type: 'resetPrintPreviewMode',
+      url: printPreviewParams.url,
+      grayscale: printPreviewParams.grayscale,
+      // If the PDF isn't modifiable we send 0 as the page count so that no
+      // blank placeholder pages get appended to the PDF.
+      pageCount:
+          (printPreviewParams.modifiable ?
+               printPreviewParams.pageNumbers.length :
+               0)
+    });
+  }
+
+  /** @param {string} newColor New color, in hex, for the PDF plugin. */
+  backgroundColorChanged(newColor) {
+    this.postMessage_({
+      type: 'backgroundColorChanged',
+      backgroundColor: newColor,
+    });
+  }
+
+  /**
+   * @param {string} url
+   * @param {number} index
+   */
+  loadPreviewPage(url, index) {
+    this.postMessage_({type: 'loadPreviewPage', url: url, index: index});
+  }
+
+  /** @param {string} password */
+  getPasswordComplete(password) {
+    this.postMessage_({type: 'getPasswordComplete', password: password});
+  }
+
+  /** @param {string} destination */
+  getNamedDestination(destination) {
+    this.postMessage_({
+      type: 'getNamedDestination',
+      namedDestination: destination,
+    });
+  }
+
+  /** @override */
+  save(requireResult) {
+    const resolver = new PromiseResolver();
+    const newToken = createToken();
+    this.pendingTokens_.set(newToken, resolver);
+    this.postMessage_({type: 'save', token: newToken, force: requireResult});
+    return resolver.promise;
+  }
+
+  /** @override */
+  async load(fileName, data) {
+    const url = URL.createObjectURL(new Blob([data]));
+    this.plugin_.removeAttribute('headers');
+    this.plugin_.setAttribute('stream-url', url);
+    this.plugin_.style.display = 'block';
+    try {
+      await this.getLoadedCallback_();
+    } finally {
+      URL.revokeObjectURL(url);
+    }
+  }
+
+  /** @override */
+  unload() {
+    this.plugin_.style.display = 'none';
+  }
+
+  /**
+   * An event handler for handling message events received from the plugin.
+   * @param {!Event} messageEvent a message event.
+   * @private
+   */
+  handlePluginMessage_(messageEvent) {
+    const messageData = /** @type {!MessageData} */ (messageEvent.data);
+    switch (messageData.type) {
+      case 'email':
+        const emailData = /** @type {!EmailMessageData} */ (messageData);
+        const href = 'mailto:' + emailData.to + '?cc=' + emailData.cc +
+            '&bcc=' + emailData.bcc + '&subject=' + emailData.subject +
+            '&body=' + emailData.body;
+        window.location.href = href;
+        break;
+      case 'goToPage':
+        this.viewport_.goToPage(
+            /** @type {{type: string, page: number}} */ (messageData).page);
+        break;
+      case 'setScrollPosition':
+        this.viewport_.scrollTo(/** @type {!PartialPoint} */ (messageData));
+        break;
+      case 'scrollBy':
+        this.viewport_.scrollBy(/** @type {!Point} */ (messageData));
+        break;
+      case 'saveData':
+        this.saveData_(/** @type {!SaveDataMessageData} */ (messageData));
+        break;
+      case 'consumeSaveToken':
+        const saveTokenData =
+            /** @type {{ type: string, token: string }} */ (messageData);
+        const resolver = this.pendingTokens_.get(saveTokenData.token);
+        assert(this.pendingTokens_.delete(saveTokenData.token));
+        resolver.resolve(null);
+        break;
+      default:
+        this.eventTarget_.dispatchEvent(
+            new CustomEvent('plugin-message', {detail: messageData}));
+    }
+  }
+
+  /**
+   * Handles the pdf file buffer received from the plugin.
+   *
+   * @param {!SaveDataMessageData} messageData data of the message event.
+   * @private
+   */
+  saveData_(messageData) {
+    assert(
+        loadTimeData.getBoolean('pdfFormSaveEnabled') ||
+        loadTimeData.getBoolean('pdfAnnotationsEnabled'));
+
+    // Verify a token that was created by this instance is included to avoid
+    // being spammed.
+    const resolver = this.pendingTokens_.get(messageData.token);
+    assert(this.pendingTokens_.delete(messageData.token));
+
+    if (!messageData.dataToSave) {
+      resolver.reject();
+      return;
+    }
+
+    // Verify the file size and the first bytes to make sure it's a PDF. Cap at
+    // 100 MB. This cap should be kept in sync with and is also enforced in
+    // pdf/out_of_process_instance.cc.
+    const MIN_FILE_SIZE = '%PDF1.0'.length;
+    const MAX_FILE_SIZE = 100 * 1000 * 1000;
+
+    const buffer = messageData.dataToSave;
+    const bufView = new Uint8Array(buffer);
+    assert(
+        bufView.length <= MAX_FILE_SIZE,
+        `File too large to be saved: ${bufView.length} bytes.`);
+    assert(bufView.length >= MIN_FILE_SIZE);
+    assert(
+        String.fromCharCode(bufView[0], bufView[1], bufView[2], bufView[3]) ==
+        '%PDF');
+
+    resolver.resolve(messageData);
+  }
+}
diff --git a/chromium/chrome/browser/resources/pdf/elements/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/BUILD.gn
new file mode 100644
index 00000000000..248059ae74f
--- /dev/null
+++ b/chromium/chrome/browser/resources/pdf/elements/BUILD.gn
@@ -0,0 +1,118 @@
+# Copyright 2019 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//third_party/closure_compiler/compile_js.gni")
+import("//tools/polymer/polymer.gni")
+
+js_type_check("closure_compile") {
+  deps = [
+    ":viewer-bookmark",
+    ":viewer-error-screen",
+    ":viewer-page-indicator",
+    ":viewer-page-selector",
+    ":viewer-password-screen",
+    ":viewer-pdf-toolbar",
+    ":viewer-toolbar-dropdown",
+    ":viewer-zoom-button",
+    ":viewer-zoom-toolbar",
+  ]
+  if (is_chromeos) {
+    deps += [
+      ":viewer-form-warning",
+      ":viewer-ink-host",
+      ":viewer-pen-options",
+    ]
+  }
+}
+
+js_library("viewer-bookmark") {
+  deps = [
+    "//third_party/polymer/v1_0/components-chromium/iron-a11y-keys-behavior:iron-a11y-keys-behavior-extracted",
+  ]
+}
+
+js_library("viewer-error-screen") {
+  deps = [
+    "//ui/webui/resources/cr_elements/cr_dialog:cr_dialog",
+  ]
+}
+
+if (is_chromeos) {
+  js_library("viewer-form-warning") {
+    deps = [
+      "//ui/webui/resources/cr_elements/cr_dialog:cr_dialog",
+      "//ui/webui/resources/js:promise_resolver",
+    ]
+  }
+
+  js_library("viewer-ink-host") {
+    deps = [
+      "//chrome/browser/resources/pdf:metrics",
+      "//chrome/browser/resources/pdf:viewport",
+      "//chrome/browser/resources/pdf/ink:ink_api",
+    ]
+  }
+}
+
+js_library("viewer-page-indicator") {
+  deps = [
+    "//ui/webui/resources/js:assert",
+    "//ui/webui/resources/js:util",
+  ]
+}
+
+js_library("viewer-page-selector") {
+  deps = [
+    "//ui/webui/resources/cr_elements/cr_input:cr_input",
+  ]
+}
+
+js_library("viewer-password-screen") {
+  deps = [
+    "//ui/webui/resources/cr_elements/cr_input:cr_input",
+  ]
+}
+
+js_library("viewer-pdf-toolbar") {
+  deps = [
+    ":viewer-bookmark",
+    ":viewer-page-selector",
+    ":viewer-toolbar-dropdown",
+    "..:annotation_tool",
+  ]
+  externs_list = [ "$externs_path/pending.js" ]
+}
+
+js_library("viewer-pen-options") {
+  externs_list = [ "$externs_path/pending_polymer.js" ]
+}
+
+js_library("viewer-toolbar-dropdown") {
+  deps = []
+}
+
+js_library("viewer-zoom-toolbar") {
+  deps = [
+    ":viewer-zoom-button",
+    "..:pdf_fitting_type",
+    "//ui/webui/resources/js:assert",
+    "//ui/webui/resources/js:util",
+  ]
+}
+
+js_library("viewer-zoom-button") {
+  deps = []
+}
+
+polymer_modulizer("shared-vars") {
+  js_file = "shared-vars.m.js"
+  html_file = "shared-vars.html"
+  html_type = "custom-style"
+}
+
+group("polymer3_elements") {
+  deps = [
+    ":shared-vars_module",
+  ]
+}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.html b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark.html
index 004aa1b1677..004aa1b1677 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark.js
index f1cce48abaa..f25ebcef472 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark.js
@@ -7,8 +7,9 @@
  *
  * The bookmark may point at a location in the PDF or a URI.
  * If it points at a location, |page| indicates which 0-based page it leads to.
- * Optionally, |y| is the y position in that page, in pixel coordinates.
- * If it points at an URI, |uri| is the target for that bookmark.
+ * Optionally, |x| is the x position in that page, |y| is the y position in that
+ * page, in pixel coordinates and |zoom| is the new zoom value. If it points at
+ * an URI, |uri| is the target for that bookmark.
  *
  * |children| is an array of the |Bookmark|s that are below this in a table of
  * contents tree
@@ -16,7 +17,9 @@
  * @typedef {{
  *   title: string,
  *   page: (number | undefined),
+ *   x: (number | undefined),
  *   y: (number | undefined),
+ *   zoom: (number | undefined),
  *   uri: (string | undefined),
  *   children: !Array<!Bookmark>
  * }}
@@ -80,11 +83,15 @@ Polymer({
 
   /** @private */
   onClick_: function() {
-    if (this.bookmark.hasOwnProperty('page')) {
-      if (this.bookmark.hasOwnProperty('y')) {
+    if (this.bookmark.page != null) {
+      if (this.bookmark.zoom != null) {
+        this.fire('change-zoom', {zoom: this.bookmark.zoom});
+      }
+      if (this.bookmark.x != null &&
+          this.bookmark.y != null) {
         this.fire('change-page-and-xy', {
           page: this.bookmark.page,
-          x: 0,
+          x: this.bookmark.x,
           y: this.bookmark.y,
           origin: 'bookmark'
         });
@@ -92,7 +99,7 @@ Polymer({
         this.fire(
             'change-page', {page: this.bookmark.page, origin: 'bookmark'});
       }
-    } else if (this.bookmark.hasOwnProperty('uri')) {
+    } else if (this.bookmark.uri != null) {
       this.fire('navigate', {uri: this.bookmark.uri, newtab: true});
     }
   },
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/BUILD.gn
deleted file mode 100644
index fa2b15b86f7..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/BUILD.gn
+++ /dev/null
@@ -1,17 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-bookmark",
-  ]
-}
-
-js_library("viewer-bookmark") {
-  deps = [
-    "//third_party/polymer/v1_0/components-chromium/iron-a11y-keys-behavior:iron-a11y-keys-behavior-extracted",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/viewer-error-screen.html b/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen.html
index 25737d45127..25737d45127 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/viewer-error-screen.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/viewer-error-screen.js b/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen.js
index 082220a4c92..082220a4c92 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/viewer-error-screen.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/BUILD.gn
deleted file mode 100644
index 3beeb5d21b0..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-error-screen/BUILD.gn
+++ /dev/null
@@ -1,17 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-error-screen",
-  ]
-}
-
-js_library("viewer-error-screen") {
-  deps = [
-    "//ui/webui/resources/cr_elements/cr_dialog:cr_dialog",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/viewer-form-warning.html b/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning.html
index 1e9e1ee4f67..1e9e1ee4f67 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/viewer-form-warning.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/viewer-form-warning.js b/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning.js
index 539eddd6b67..539eddd6b67 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/viewer-form-warning.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/BUILD.gn
deleted file mode 100644
index e27ead67627..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-form-warning/BUILD.gn
+++ /dev/null
@@ -1,18 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-form-warning",
-  ]
-}
-
-js_library("viewer-form-warning") {
-  deps = [
-    "//ui/webui/resources/cr_elements/cr_dialog:cr_dialog",
-    "//ui/webui/resources/js:promise_resolver",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/viewer-ink-host.html b/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host.html
index 1a7a2ff73ea..1a7a2ff73ea 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/viewer-ink-host.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/viewer-ink-host.js b/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host.js
index 285edf8a35d..285edf8a35d 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/viewer-ink-host.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/BUILD.gn
deleted file mode 100644
index 32ca2b04311..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-ink-host/BUILD.gn
+++ /dev/null
@@ -1,19 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-ink-host",
-  ]
-}
-
-js_library("viewer-ink-host") {
-  deps = [
-    "//chrome/browser/resources/pdf:metrics",
-    "//chrome/browser/resources/pdf:viewport",
-    "//chrome/browser/resources/pdf/ink:ink_api",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/viewer-page-indicator.html b/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator.html
index 70ad2578685..70ad2578685 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/viewer-page-indicator.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/viewer-page-indicator.js b/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator.js
index 50ad4f4cb49..50ad4f4cb49 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/viewer-page-indicator.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/BUILD.gn
deleted file mode 100644
index aa1906c65e5..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-indicator/BUILD.gn
+++ /dev/null
@@ -1,18 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-page-indicator",
-  ]
-}
-
-js_library("viewer-page-indicator") {
-  deps = [
-    "//ui/webui/resources/js:assert",
-    "//ui/webui/resources/js:util",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/viewer-page-selector.html b/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector.html
index e1fdc869efe..e1fdc869efe 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/viewer-page-selector.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/viewer-page-selector.js b/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector.js
index b7999237a98..b7999237a98 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/viewer-page-selector.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/BUILD.gn
deleted file mode 100644
index 725e3f96591..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-page-selector/BUILD.gn
+++ /dev/null
@@ -1,17 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-page-selector",
-  ]
-}
-
-js_library("viewer-page-selector") {
-  deps = [
-    "//ui/webui/resources/cr_elements/cr_input:cr_input",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/viewer-password-screen.html b/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen.html
index aebc16bf138..aebc16bf138 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/viewer-password-screen.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/viewer-password-screen.js b/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen.js
index 5506ad2915c..5506ad2915c 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/viewer-password-screen.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/BUILD.gn
deleted file mode 100644
index 5078ae7403f..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-password-screen/BUILD.gn
+++ /dev/null
@@ -1,17 +0,0 @@
-# Copyright 2018 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-password-screen",
-  ]
-}
-
-js_library("viewer-password-screen") {
-  deps = [
-    "//ui/webui/resources/cr_elements/cr_input:cr_input",
-  ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/viewer-pdf-toolbar.html b/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar.html
index e183debc86d..348e2215fed 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/viewer-pdf-toolbar.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar.html
@@ -4,13 +4,13 @@
 <link rel="import" href="chrome://resources/cr_elements/hidden_style_css.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-progress/paper-progress.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
-<link rel="import" href="../icons.html">
-<link rel="import" href="../viewer-bookmark/viewer-bookmark.html">
-<link rel="import" href="../viewer-page-selector/viewer-page-selector.html">
+<link rel="import" href="icons.html">
+<link rel="import" href="viewer-bookmark.html">
+<link rel="import" href="viewer-page-selector.html">
 <if expr="chromeos">
-<link rel="import" href="../viewer-pen-options/viewer-pen-options.html">
+<link rel="import" href="viewer-pen-options.html">
 </if>
-<link rel="import" href="../viewer-toolbar-dropdown/viewer-toolbar-dropdown.html">
+<link rel="import" href="viewer-toolbar-dropdown.html">
 
 <dom-module id="viewer-pdf-toolbar">
   <template>
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/viewer-pdf-toolbar.js b/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar.js
index afb87dfe6b7..07407cfee75 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/viewer-pdf-toolbar.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar.js
@@ -1,6 +1,7 @@
 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
+
 (function() {
 Polymer({
   is: 'viewer-pdf-toolbar',
@@ -24,7 +25,7 @@ Polymer({
       reflectToAttribute: true,
     },
 
-    /** @type {?Object} */
+    /** @type {?AnnotationTool} */
     annotationTool: {
       type: Object,
       value: null,
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/BUILD.gn
deleted file mode 100644
index fdc650f55b9..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pdf-toolbar/BUILD.gn
+++ /dev/null
@@ -1,20 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-pdf-toolbar",
-  ]
-}
-
-js_library("viewer-pdf-toolbar") {
-  deps = [
-    "../viewer-bookmark:viewer-bookmark",
-    "../viewer-page-selector:viewer-page-selector",
-    "../viewer-toolbar-dropdown:viewer-toolbar-dropdown",
-  ]
-  externs_list = [ "$externs_path/pending.js" ]
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/viewer-pen-options.html b/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options.html
index dbf18b0bfda..dbf18b0bfda 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/viewer-pen-options.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/viewer-pen-options.js b/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options.js
index 3970e0ff630..d63343404fb 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/viewer-pen-options.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options.js
@@ -81,7 +81,7 @@ Polymer({
     strings: Object,
   },
 
-  /** @type {Array<Animation>} */
+  /** @type {Array<!Animation>} */
   expandAnimations_: null,
 
   /** @param {Event} e */
@@ -103,7 +103,8 @@ Polymer({
   /** @private */
   updateExpandedStateAndFinishAnimations_: function() {
     this.updateExpandedState_();
-    for (const animation of this.expandAnimations_) {
+    for (const animation of /** @type {!Array<!Animation>} */ (
+             this.expandAnimations_)) {
       animation.finish();
     }
   },
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/BUILD.gn
deleted file mode 100644
index b542932ff9c..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-pen-options/BUILD.gn
+++ /dev/null
@@ -1,14 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-pen-options",
-  ]
-}
-
-js_library("viewer-pen-options") {
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/viewer-toolbar-dropdown.html b/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown.html
index 1ebf0df604f..1ebf0df604f 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/viewer-toolbar-dropdown.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/viewer-toolbar-dropdown.js b/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown.js
index 00b2b676b45..191f4cfcfbf 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/viewer-toolbar-dropdown.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown.js
@@ -216,5 +216,4 @@ Polymer({
         });
   }
 });
-
 })();
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/BUILD.gn
deleted file mode 100644
index 7a2ca5ce91a..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-toolbar-dropdown/BUILD.gn
+++ /dev/null
@@ -1,15 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-toolbar-dropdown",
-  ]
-}
-
-js_library("viewer-toolbar-dropdown") {
-  deps = []
-}
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-button.html b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-button.html
index 000d098cfb3..000d098cfb3 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-button.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-button.html
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-button.js b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-button.js
index 2359900d83c..2359900d83c 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-button.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-button.js
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.html b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar.html
index e0f2bdd15ba..0807c5dfe64 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.html
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar.html
@@ -1,7 +1,7 @@
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/util.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
-<link rel="import" href="../icons.html">
+<link rel="import" href="icons.html">
 <link rel="import" href="viewer-zoom-button.html">
 
 <dom-module id="viewer-zoom-toolbar">
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar.js
index fe24ab64645..fe28ef8c96a 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar.js
@@ -2,6 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+/**
+ * @typedef {{
+ *   fittingType: !FittingType,
+ *   userInitiated: boolean,
+ * }}
+ */
+let FitToChangedEvent;
+
 (function() {
 
 const FIT_TO_PAGE_BUTTON_STATE = 0;
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/BUILD.gn b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/BUILD.gn
deleted file mode 100644
index 4c75971c261..00000000000
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/BUILD.gn
+++ /dev/null
@@ -1,25 +0,0 @@
-# Copyright 2019 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-import("//third_party/closure_compiler/compile_js.gni")
-
-js_type_check("closure_compile") {
-  deps = [
-    ":viewer-zoom-button",
-    ":viewer-zoom-toolbar",
-  ]
-}
-
-js_library("viewer-zoom-toolbar") {
-  deps = [
-    ":viewer-zoom-button",
-    "../..:pdf_fitting_type",
-    "//ui/webui/resources/js:assert",
-    "//ui/webui/resources/js:util",
-  ]
-}
-
-js_library("viewer-zoom-button") {
-  deps = []
-}
diff --git a/chromium/chrome/browser/resources/pdf/index.html b/chromium/chrome/browser/resources/pdf/index.html
index 06d219a6c7e..00d96432fd0 100644
--- a/chromium/chrome/browser/resources/pdf/index.html
+++ b/chromium/chrome/browser/resources/pdf/index.html
@@ -4,20 +4,20 @@
   <meta charset="utf-8">
   <script src="chrome://resources/polymer/v1_0/html-imports/html-imports.min.js">
   </script>
-  <link rel="import" href="elements/viewer-error-screen/viewer-error-screen.html">
-  <link rel="import" href="elements/viewer-page-indicator/viewer-page-indicator.html">
-  <link rel="import" href="elements/viewer-page-selector/viewer-page-selector.html">
-  <link rel="import" href="elements/viewer-password-screen/viewer-password-screen.html">
-  <link rel="import" href="elements/viewer-pdf-toolbar/viewer-pdf-toolbar.html">
-  <link rel="import" href="elements/viewer-zoom-toolbar/viewer-zoom-toolbar.html">
+  <link rel="import" href="elements/viewer-error-screen.html">
+  <link rel="import" href="elements/viewer-page-indicator.html">
+  <link rel="import" href="elements/viewer-page-selector.html">
+  <link rel="import" href="elements/viewer-password-screen.html">
+  <link rel="import" href="elements/viewer-pdf-toolbar.html">
+  <link rel="import" href="elements/viewer-zoom-toolbar.html">
   <link rel="import" href="elements/shared-vars.html">
   <link rel="import" href="chrome://resources/cr_elements/cr_dialog/cr_dialog.html">
   <link rel="import" href="chrome://resources/html/cr/event_target.html">
   <link rel="import" href="chrome://resources/html/event_tracker.html">
 
 <if expr="chromeos">
-  <link rel="import" href="elements/viewer-ink-host/viewer-ink-host.html">
-  <link rel="import" href="elements/viewer-form-warning/viewer-form-warning.html">
+  <link rel="import" href="elements/viewer-ink-host.html">
+  <link rel="import" href="elements/viewer-form-warning.html">
 </if>
 
   <link rel="stylesheet" href="chrome://resources/css/text_defaults_md.css">
@@ -58,6 +58,7 @@
 <script src="chrome://resources/js/promise_resolver.js"></script>
 <script src="browser_api.js"></script>
 <script src="metrics.js"></script>
+<script src="controller.js"></script>
 <script src="pdf_viewer.js"></script>
 <script src="main.js"></script>
 </html>
diff --git a/chromium/chrome/browser/resources/pdf/ink/BUILD.gn b/chromium/chrome/browser/resources/pdf/ink/BUILD.gn
index 38908ee25a1..b1c2be215bd 100644
--- a/chromium/chrome/browser/resources/pdf/ink/BUILD.gn
+++ b/chromium/chrome/browser/resources/pdf/ink/BUILD.gn
@@ -11,6 +11,9 @@ js_type_check("closure_compile") {
 }
 
 js_library("ink_api") {
+  deps = [
+    "..:annotation_tool",
+  ]
   externs_list = [
     "//third_party/ink/build/ink_lib_externs.js",
     "$externs_path/pending.js",
diff --git a/chromium/chrome/browser/resources/pdf/ink/ink_api.js b/chromium/chrome/browser/resources/pdf/ink/ink_api.js
index 04e0d56dcf6..99eed15d900 100644
--- a/chromium/chrome/browser/resources/pdf/ink/ink_api.js
+++ b/chromium/chrome/browser/resources/pdf/ink/ink_api.js
@@ -4,15 +4,6 @@
 
 /**
  * @typedef {{
- *   tool: string,
- *   size: number,
- *   color: string,
- * }}
- */
-let AnnotationTool;
-
-/**
- * @typedef {{
  *   canUndo: boolean,
  *   canRedo: boolean,
  * }}
@@ -88,7 +79,7 @@ class InkAPI {
     }[tool.tool];
     this.brush_.setShape(shape);
     if (tool.tool != 'eraser') {
-      this.brush_.setColor(tool.color);
+      this.brush_.setColor(/** @type {string} */ (tool.color));
     }
     this.brush_.setStrokeWidth(tool.size);
   }
diff --git a/chromium/chrome/browser/resources/pdf/open_pdf_params_parser.js b/chromium/chrome/browser/resources/pdf/open_pdf_params_parser.js
index d4a502a135f..c33c46b6d75 100644
--- a/chromium/chrome/browser/resources/pdf/open_pdf_params_parser.js
+++ b/chromium/chrome/browser/resources/pdf/open_pdf_params_parser.js
@@ -10,15 +10,15 @@
  */
 class OpenPdfParamsParser {
   /**
-   * @param {function(Object)} postMessageCallback
+   * @param {function(string):void} getNamedDestinationCallback
    *     Function called to fetch information for a named destination.
    */
-  constructor(postMessageCallback) {
+  constructor(getNamedDestinationCallback) {
     /** @private {!Array<!Object>} */
     this.outstandingRequests_ = [];
 
-    /** @private {!function(Object)} */
-    this.postMessageCallback_ = postMessageCallback;
+    /** @private {!function(string):void} */
+    this.getNamedDestinationCallback_ = getNamedDestinationCallback;
   }
 
   /**
@@ -181,10 +181,7 @@ class OpenPdfParamsParser {
 
     if (params.page === undefined && 'nameddest' in urlParams) {
       this.outstandingRequests_.push({callback: callback, params: params});
-      this.postMessageCallback_({
-        type: 'getNamedDestination',
-        namedDestination: urlParams['nameddest']
-      });
+      this.getNamedDestinationCallback_(urlParams['nameddest']);
     } else {
       callback(params);
     }
diff --git a/chromium/chrome/browser/resources/pdf/pdf_scripting_api.js b/chromium/chrome/browser/resources/pdf/pdf_scripting_api.js
index 0ab77f41f3f..5957e13c178 100644
--- a/chromium/chrome/browser/resources/pdf/pdf_scripting_api.js
+++ b/chromium/chrome/browser/resources/pdf/pdf_scripting_api.js
@@ -6,7 +6,7 @@
  * Turn a dictionary received from postMessage into a key event.
  *
  * @param {Object} dict A dictionary representing the key event.
- * @return {Event} A key event.
+ * @return {!Event} A key event.
  */
 function DeserializeKeyEvent(dict) {
   const e = document.createEvent('Event');
@@ -53,66 +53,83 @@ const LoadState = {
  * Create a new PDFScriptingAPI. This provides a scripting interface to
  * the PDF viewer so that it can be customized by things like print preview.
  *
- * @param {Window} window the window of the page containing the pdf viewer.
- * @param {Object} plugin the plugin element containing the pdf viewer.
- * @constructor
  */
-function PDFScriptingAPI(window, plugin) {
-  this.loadState_ = LoadState.LOADING;
-  this.pendingScriptingMessages_ = [];
-  this.setPlugin(plugin);
+class PDFScriptingAPI {
+  /**
+   * @param {Window} window the window of the page containing the pdf viewer.
+   * @param {Object} plugin the plugin element containing the pdf viewer.
+   */
+  constructor(window, plugin) {
+    this.loadState_ = LoadState.LOADING;
+    this.pendingScriptingMessages_ = [];
+    this.setPlugin(plugin);
 
-  window.addEventListener('message', event => {
-    if (event.origin != 'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai' &&
-        event.origin != 'chrome://print') {
-      console.error(
-          'Received message that was not from the extension: ' + event);
-      return;
-    }
-    switch (event.data.type) {
-      case 'viewport':
-        /**
-         * @type {{
-         *   pageX: number,
-         *   pageY: number,
-         *   pageWidth: number,
-         *   viewportWidth: number,
-         *   viewportHeight: number
-         * }}
-         */
-        const viewportData = event.data;
-        if (this.viewportChangedCallback_) {
-          this.viewportChangedCallback_(
-              viewportData.pageX, viewportData.pageY, viewportData.pageWidth,
-              viewportData.viewportWidth, viewportData.viewportHeight);
-        }
-        break;
-      case 'documentLoaded': {
-        const data = /** @type {{load_state: LoadState}} */ (event.data);
-        this.loadState_ = data.load_state;
-        if (this.loadCallback_) {
-          this.loadCallback_(this.loadState_ == LoadState.SUCCESS);
-        }
-        break;
+    /** @private {Function} */
+    this.viewportChangedCallback_;
+
+    /** @private {Function} */
+    this.loadCallback_;
+
+    /** @private {Function} */
+    this.selectedTextCallback_;
+
+    /** @private {Function} */
+    this.keyEventCallback_;
+
+    /** @private {Object} */
+    this.plugin_;
+
+    window.addEventListener('message', event => {
+      if (event.origin !=
+              'chrome-extension://mhjfbmdgcfjbbpaeojofohoefgiehjai' &&
+          event.origin != 'chrome://print') {
+        console.error(
+            'Received message that was not from the extension: ' + event);
+        return;
       }
-      case 'getSelectedTextReply': {
-        const data = /** @type {{selectedText: string}} */ (event.data);
-        if (this.selectedTextCallback_) {
-          this.selectedTextCallback_(data.selectedText);
-          this.selectedTextCallback_ = null;
+      switch (event.data.type) {
+        case 'viewport':
+          /**
+           * @type {{
+           *   pageX: number,
+           *   pageY: number,
+           *   pageWidth: number,
+           *   viewportWidth: number,
+           *   viewportHeight: number
+           * }}
+           */
+          const viewportData = event.data;
+          if (this.viewportChangedCallback_) {
+            this.viewportChangedCallback_(
+                viewportData.pageX, viewportData.pageY, viewportData.pageWidth,
+                viewportData.viewportWidth, viewportData.viewportHeight);
+          }
+          break;
+        case 'documentLoaded': {
+          const data = /** @type {{load_state: LoadState}} */ (event.data);
+          this.loadState_ = data.load_state;
+          if (this.loadCallback_) {
+            this.loadCallback_(this.loadState_ == LoadState.SUCCESS);
+          }
+          break;
         }
-        break;
-      }
-      case 'sendKeyEvent':
-        if (this.keyEventCallback_) {
-          this.keyEventCallback_(DeserializeKeyEvent(event.data.keyEvent));
+        case 'getSelectedTextReply': {
+          const data = /** @type {{selectedText: string}} */ (event.data);
+          if (this.selectedTextCallback_) {
+            this.selectedTextCallback_(data.selectedText);
+            this.selectedTextCallback_ = null;
+          }
+          break;
         }
-        break;
-    }
-  }, false);
-}
+        case 'sendKeyEvent':
+          if (this.keyEventCallback_) {
+            this.keyEventCallback_(DeserializeKeyEvent(event.data.keyEvent));
+          }
+          break;
+      }
+    }, false);
+  }
 
-PDFScriptingAPI.prototype = {
   /**
    * Send a message to the extension. If messages try to get sent before there
    * is a plugin element set, then we queue them up and send them later (this
@@ -121,13 +138,13 @@ PDFScriptingAPI.prototype = {
    * @param {Object} message The message to send.
    * @private
    */
-  sendMessage_: function(message) {
+  sendMessage_(message) {
     if (this.plugin_) {
       this.plugin_.postMessage(message, '*');
     } else {
       this.pendingScriptingMessages_.push(message);
     }
-  },
+  }
 
   /**
    * Sets the plugin element containing the PDF viewer. The element will usually
@@ -135,7 +152,7 @@ PDFScriptingAPI.prototype = {
    *
    * @param {Object} plugin the plugin element containing the PDF viewer.
    */
-  setPlugin: function(plugin) {
+  setPlugin(plugin) {
     this.plugin_ = plugin;
 
     if (this.plugin_) {
@@ -147,16 +164,16 @@ PDFScriptingAPI.prototype = {
         this.sendMessage_(this.pendingScriptingMessages_.shift());
       }
     }
-  },
+  }
 
   /**
    * Sets the callback which will be run when the PDF viewport changes.
    *
    * @param {Function} callback the callback to be called.
    */
-  setViewportChangedCallback: function(callback) {
+  setViewportChangedCallback(callback) {
     this.viewportChangedCallback_ = callback;
-  },
+  }
 
   /**
    * Sets the callback which will be run when the PDF document has finished
@@ -164,20 +181,20 @@ PDFScriptingAPI.prototype = {
    *
    * @param {Function} callback the callback to be called.
    */
-  setLoadCallback: function(callback) {
+  setLoadCallback(callback) {
     this.loadCallback_ = callback;
     if (this.loadState_ != LoadState.LOADING && this.loadCallback_) {
       this.loadCallback_(this.loadState_ == LoadState.SUCCESS);
     }
-  },
+  }
 
   /**
    * Sets a callback that gets run when a key event is fired in the PDF viewer.
    * @param {Function} callback the callback to be called with a key event.
    */
-  setKeyEventCallback: function(callback) {
+  setKeyEventCallback(callback) {
     this.keyEventCallback_ = callback;
-  },
+  }
 
   /**
    * Resets the PDF viewer into print preview mode.
@@ -187,7 +204,7 @@ PDFScriptingAPI.prototype = {
    * @param {Array<number>} pageNumbers an array of the page numbers.
    * @param {boolean} modifiable whether or not the document is modifiable.
    */
-  resetPrintPreviewMode: function(url, grayscale, pageNumbers, modifiable) {
+  resetPrintPreviewMode(url, grayscale, pageNumbers, modifiable) {
     this.loadState_ = LoadState.LOADING;
     this.sendMessage_({
       type: 'resetPrintPreviewMode',
@@ -196,14 +213,14 @@ PDFScriptingAPI.prototype = {
       pageNumbers: pageNumbers,
       modifiable: modifiable
     });
-  },
+  }
 
   /**
    * Hide the toolbars after a delay.
    */
-  hideToolbars: function() {
+  hideToolbars() {
     this.sendMessage_({type: 'hideToolbars'});
-  },
+  }
 
   /**
    * Load a page into the document while in print preview mode.
@@ -211,22 +228,22 @@ PDFScriptingAPI.prototype = {
    * @param {string} url the url of the pdf page to load.
    * @param {number} index the index of the page to load.
    */
-  loadPreviewPage: function(url, index) {
+  loadPreviewPage(url, index) {
     this.sendMessage_({type: 'loadPreviewPage', url: url, index: index});
-  },
+  }
 
   /** @param {boolean} darkMode Whether the page is in dark mode. */
-  darkModeChanged: function(darkMode) {
+  darkModeChanged(darkMode) {
     this.sendMessage_({type: 'darkModeChanged', darkMode: darkMode});
-  },
+  }
 
   /**
    * Select all the text in the document. May only be called after document
    * load.
    */
-  selectAll: function() {
+  selectAll() {
     this.sendMessage_({type: 'selectAll'});
-  },
+  }
 
   /**
    * Get the selected text in the document. The callback will be called with the
@@ -236,40 +253,40 @@ PDFScriptingAPI.prototype = {
    * @return {boolean} true if the function is successful, false if there is an
    *     outstanding request for selected text that has not been answered.
    */
-  getSelectedText: function(callback) {
+  getSelectedText(callback) {
     if (this.selectedTextCallback_) {
       return false;
     }
     this.selectedTextCallback_ = callback;
     this.sendMessage_({type: 'getSelectedText'});
     return true;
-  },
+  }
 
   /**
    * Print the document. May only be called after document load.
    */
-  print: function() {
+  print() {
     this.sendMessage_({type: 'print'});
-  },
+  }
 
   /**
    * Send a key event to the extension.
    *
    * @param {Event} keyEvent the key event to send to the extension.
    */
-  sendKeyEvent: function(keyEvent) {
+  sendKeyEvent(keyEvent) {
     this.sendMessage_(
         {type: 'sendKeyEvent', keyEvent: SerializeKeyEvent(keyEvent)});
-  },
+  }
 
   /**
    * @param {number} scrollX The amount to horizontally scroll in pixels.
    * @param {number} scrollY The amount to vertically scroll in pixels.
    */
-  scrollPosition: function(scrollX, scrollY) {
+  scrollPosition(scrollX, scrollY) {
     this.sendMessage_({type: 'scrollPosition', x: scrollX, y: scrollY});
-  },
-};
+  }
+}
 
 /**
  * Creates a PDF viewer with a scripting interface. This is basically 1) an
diff --git a/chromium/chrome/browser/resources/pdf/pdf_viewer.js b/chromium/chrome/browser/resources/pdf/pdf_viewer.js
index 375663f029c..d85d80a2101 100644
--- a/chromium/chrome/browser/resources/pdf/pdf_viewer.js
+++ b/chromium/chrome/browser/resources/pdf/pdf_viewer.js
@@ -6,16 +6,64 @@
 
 /**
  * @typedef {{
- *   dataToSave: Array,
- *   token: string,
- *   fileName: string
+ *   source: Object,
+ *   origin: string,
+ *   data: !MessageData,
  * }}
  */
-let SaveDataMessageData;
+let MessageObject;
 
 /**
- * @return {number} Width of a scrollbar in pixels
+ * @typedef {{
+ *   type: string,
+ *   height: number,
+ *   width: number,
+ *   layoutOptions: (!LayoutOptions|undefined),
+ *   pageDimensions: Array
+ * }}
+ */
+let DocumentDimensionsMessageData;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   url: string,
+ *   disposition: !PdfNavigator.WindowOpenDisposition,
+ * }}
+ */
+let NavigateMessageData;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   page: number,
+ *   x: number,
+ *   y: number,
+ *   zoom: number
+ * }}
+ */
+let DestinationMessageData;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   title: string,
+ *   bookmarks: !Array<!Bookmark>,
+ *   canSerializeDocument: boolean,
+ * }}
  */
+let MetadataMessageData;
+
+/**
+ * @typedef {{
+ *   hasUnsavedChanges: (boolean|undefined),
+ *   fileName: string,
+ *   dataToSave: !ArrayBuffer
+ * }}
+ */
+let RequiredSaveResult;
+
+/** @return {number} Width of a scrollbar in pixels */
 function getScrollbarWidth() {
   const div = document.createElement('div');
   div.style.visibility = 'hidden';
@@ -31,7 +79,6 @@ function getScrollbarWidth() {
 
 /**
  * Return the filename component of a URL, percent decoded if possible.
- *
  * @param {string} url The URL to get the filename from.
  * @return {string} The filename component.
  */
@@ -53,8 +100,7 @@ function getFilenameFromURL(url) {
 /**
  * Whether keydown events should currently be ignored. Events are ignored when
  * an editable element has focus, to allow for proper editing controls.
- *
- * @param {HTMLElement} activeElement The currently selected DOM node.
+ * @param {Element} activeElement The currently selected DOM node.
  * @return {boolean} True if keydown events should be ignored.
  */
 function shouldIgnoreKeyEvents(activeElement) {
@@ -70,285 +116,341 @@ function shouldIgnoreKeyEvents(activeElement) {
 }
 
 /**
- * Creates a cryptographically secure pseudorandom 128-bit token.
- *
- * @return {string} The generated token as a hex string.
+ * Creates a new PDFViewer. There should only be one of these objects per
+ * document.
  */
-function createToken() {
-  const randomBytes = new Uint8Array(16);
-  return window.crypto.getRandomValues(randomBytes)
-      .map(b => b.toString(16).padStart(2, '0'))
-      .join('');
-}
+class PDFViewer {
+  /**
+   * @param {!BrowserApi} browserApi An object providing an API to the browser.
+   */
+  constructor(browserApi) {
+    /** @private {!BrowserApi} */
+    this.browserApi_ = browserApi;
 
-/**
- * The minimum number of pixels to offset the toolbar by from the bottom and
- * right side of the screen.
- */
-PDFViewer.MIN_TOOLBAR_OFFSET = 15;
+    /** @private {string} */
+    this.originalUrl_ = this.browserApi_.getStreamInfo().originalUrl;
 
-/**
- * The height of the toolbar along the top of the page. The document will be
- * shifted down by this much in the viewport.
- */
-PDFViewer.MATERIAL_TOOLBAR_HEIGHT = 56;
+    /** @private {string} */
+    this.javascript_ = this.browserApi_.getStreamInfo().javascript || 'block';
 
-/**
- * Minimum height for the material toolbar to show (px). Should match the media
- * query in index-material.css. If the window is smaller than this at load,
- * leave no space for the toolbar.
- */
-PDFViewer.TOOLBAR_WINDOW_MIN_HEIGHT = 250;
+    /** @private {!LoadState} */
+    this.loadState_ = LoadState.LOADING;
 
-/**
- * The background color used for print preview (--google-grey-refresh-300).
- */
-PDFViewer.PRINT_PREVIEW_BACKGROUND_COLOR = '0xFFDADCE0';
+    /** @private {?Object} */
+    this.parentWindow_ = null;
 
-/**
- * The background color used for print preview when dark mode is enabled
- * (--google-grey-refresh-700).
- */
-PDFViewer.PRINT_PREVIEW_DARK_BACKGROUND_COLOR = '0xFF5F6368';
+    /** @private {?string} */
+    this.parentOrigin_ = null;
 
-/**
- * The background color used for the regular viewer.
- */
-PDFViewer.BACKGROUND_COLOR = '0xFF525659';
+    /** @private {boolean} */
+    this.isFormFieldFocused_ = false;
 
-/**
- * Creates a new PDFViewer. There should only be one of these objects per
- * document.
- *
- * @param {!BrowserApi} browserApi An object providing an API to the browser.
- * @constructor
- */
-function PDFViewer(browserApi) {
-  this.browserApi_ = browserApi;
-  this.originalUrl_ = this.browserApi_.getStreamInfo().originalUrl;
-  this.javascript_ = this.browserApi_.getStreamInfo().javascript || 'block';
-  this.loadState_ = LoadState.LOADING;
-  this.parentWindow_ = null;
-  this.parentOrigin_ = null;
-  this.isFormFieldFocused_ = false;
-  this.beepCount_ = 0;
-  this.delayedScriptingMessages_ = [];
-  this.loaded_ = new PromiseResolver();
-
-  this.isPrintPreview_ = location.origin === 'chrome://print';
-  this.isPrintPreviewLoadingFinished_ = false;
-  this.isUserInitiatedEvent_ = true;
-
-  /** @private {boolean} */
-  this.hasEnteredAnnotationMode_ = false;
-
-  /** @private {boolean} */
-  this.hadPassword_ = false;
-
-  /** @private {boolean} */
-  this.canSerializeDocument_ = false;
-
-  PDFMetrics.record(PDFMetrics.UserAction.DOCUMENT_OPENED);
-
-  // Parse open pdf parameters.
-  this.paramsParser_ = new OpenPdfParamsParser(
-      message => this.pluginController_.postMessage(message));
-  const toolbarEnabled =
-      this.paramsParser_.getUiUrlParams(this.originalUrl_).toolbar &&
-      !this.isPrintPreview_;
-
-  // The sizer element is placed behind the plugin element to cause scrollbars
-  // to be displayed in the window. It is sized according to the document size
-  // of the pdf and zoom level.
-  this.sizer_ = $('sizer');
-
-  if (this.isPrintPreview_) {
-    this.pageIndicator_ = $('page-indicator');
-  }
-  this.passwordScreen_ = $('password-screen');
-  this.passwordScreen_.addEventListener(
-      'password-submitted', e => this.onPasswordSubmitted_(e));
-  this.errorScreen_ = $('error-screen');
-  // Can only reload if we are in a normal tab.
-  if (chrome.tabs && this.browserApi_.getStreamInfo().tabId != -1) {
-    this.errorScreen_.reloadFn = () => {
-      chrome.tabs.reload(this.browserApi_.getStreamInfo().tabId);
-    };
-  }
+    /** @private {number} */
+    this.beepCount_ = 0;
 
-  // Create the viewport.
-  const shortWindow = window.innerHeight < PDFViewer.TOOLBAR_WINDOW_MIN_HEIGHT;
-  const topToolbarHeight =
-      (toolbarEnabled) ? PDFViewer.MATERIAL_TOOLBAR_HEIGHT : 0;
-  const defaultZoom =
-      this.browserApi_.getZoomBehavior() == BrowserApi.ZoomBehavior.MANAGE ?
-      this.browserApi_.getDefaultZoom() :
-      1.0;
-  this.viewport_ = new Viewport(
-      window, this.sizer_, getScrollbarWidth(), defaultZoom, topToolbarHeight);
-  this.viewport_.setViewportChangedCallback(() => this.viewportChanged_());
-  this.viewport_.setBeforeZoomCallback(
-      () => this.currentController_.beforeZoom());
-  this.viewport_.setAfterZoomCallback(
-      () => this.currentController_.afterZoom());
-  this.viewport_.setUserInitiatedCallback(
-      userInitiated => this.setUserInitiated_(userInitiated));
-  window.addEventListener('beforeunload', () => this.viewport_.resetTracker());
-
-  // Create the plugin object dynamically so we can set its src. The plugin
-  // element is sized to fill the entire window and is set to be fixed
-  // positioning, acting as a viewport. The plugin renders into this viewport
-  // according to the scroll position of the window.
-  this.plugin_ = document.createElement('embed');
-  // NOTE: The plugin's 'id' field must be set to 'plugin' since
-  // chrome/renderer/printing/print_render_frame_helper.cc actually
-  // references it.
-  this.plugin_.id = 'plugin';
-  this.plugin_.type = 'application/x-google-chrome-pdf';
-
-  // Handle scripting messages from outside the extension that wish to interact
-  // with it. We also send a message indicating that extension has loaded and
-  // is ready to receive messages.
-  window.addEventListener(
-      'message', message => this.handleScriptingMessage(message), false);
-
-  this.plugin_.setAttribute('src', this.originalUrl_);
-  this.plugin_.setAttribute(
-      'stream-url', this.browserApi_.getStreamInfo().streamUrl);
-  let headers = '';
-  for (const header in this.browserApi_.getStreamInfo().responseHeaders) {
-    headers += header + ': ' +
-        this.browserApi_.getStreamInfo().responseHeaders[header] + '\n';
-  }
-  this.plugin_.setAttribute('headers', headers);
+    /** @private {!Array} */
+    this.delayedScriptingMessages_ = [];
+
+    /** @private {!PromiseResolver} */
+    this.loaded_;
+
+    /** @private {boolean} */
+    this.initialLoadComplete_ = false;
+
+    /** @private {boolean} */
+    this.isPrintPreview_ = location.origin === 'chrome://print';
 
-  this.plugin_.setAttribute('background-color', PDFViewer.BACKGROUND_COLOR);
-  this.plugin_.setAttribute('top-toolbar-height', topToolbarHeight);
-  this.plugin_.setAttribute('javascript', this.javascript_);
+    /** @private {boolean} */
+    this.isPrintPreviewLoadingFinished_ = false;
 
-  if (this.browserApi_.getStreamInfo().embedded) {
+    /** @private {boolean} */
+    this.isUserInitiatedEvent_ = true;
+
+    /** @private {boolean} */
+    this.hasEnteredAnnotationMode_ = false;
+
+    /** @private {boolean} */
+    this.hadPassword_ = false;
+
+    /** @private {boolean} */
+    this.canSerializeDocument_ = false;
+
+    /** @private {!EventTracker} */
+    this.tracker_ = new EventTracker();
+
+    PDFMetrics.record(PDFMetrics.UserAction.DOCUMENT_OPENED);
+
+    // Parse open pdf parameters.
+    /** @private {!OpenPdfParamsParser} */
+    this.paramsParser_ = new OpenPdfParamsParser(
+        destination => this.pluginController_.getNamedDestination(destination));
+    const toolbarEnabled =
+        this.paramsParser_.getUiUrlParams(this.originalUrl_).toolbar &&
+        !this.isPrintPreview_;
+
+    // The sizer element is placed behind the plugin element to cause scrollbars
+    // to be displayed in the window. It is sized according to the document size
+    // of the pdf and zoom level.
+    this.sizer_ = /** @type {!HTMLDivElement} */ ($('sizer'));
+
+    /** @private {?ViewerPageIndicatorElement} */
+    this.pageIndicator_ = this.isPrintPreview_ ?
+        /** @type {!ViewerPageIndicatorElement} */ ($('page-indicator')) :
+        null;
+
+    /** @private {?ViewerPasswordScreenElement} */
+    this.passwordScreen_ =
+        /** @type {!ViewerPasswordScreenElement} */ ($('password-screen'));
+    this.passwordScreen_.addEventListener('password-submitted', e => {
+      this.onPasswordSubmitted_(
+          /** @type {!CustomEvent<{password: string}>} */ (e));
+    });
+
+    /** @private {?ViewerErrorScreenElement} */
+    this.errorScreen_ =
+        /** @type {!ViewerErrorScreenElement} */ ($('error-screen'));
+    // Can only reload if we are in a normal tab.
+    if (chrome.tabs && this.browserApi_.getStreamInfo().tabId != -1) {
+      this.errorScreen_.reloadFn = () => {
+        chrome.tabs.reload(this.browserApi_.getStreamInfo().tabId);
+      };
+    }
+
+    // Create the viewport.
+    const shortWindow =
+        window.innerHeight < PDFViewer.TOOLBAR_WINDOW_MIN_HEIGHT;
+    const topToolbarHeight =
+        (toolbarEnabled) ? PDFViewer.MATERIAL_TOOLBAR_HEIGHT : 0;
+    const defaultZoom =
+        this.browserApi_.getZoomBehavior() == BrowserApi.ZoomBehavior.MANAGE ?
+        this.browserApi_.getDefaultZoom() :
+        1.0;
+
+    /** @private {!Viewport} */
+    this.viewport_ = new Viewport(
+        window, this.sizer_, getScrollbarWidth(), defaultZoom,
+        topToolbarHeight);
+    this.viewport_.setViewportChangedCallback(() => this.viewportChanged_());
+    this.viewport_.setBeforeZoomCallback(
+        () => this.currentController_.beforeZoom());
+    this.viewport_.setAfterZoomCallback(
+        () => this.currentController_.afterZoom());
+    this.viewport_.setUserInitiatedCallback(
+        userInitiated => this.setUserInitiated_(userInitiated));
+    window.addEventListener('beforeunload', () => this.resetTrackers_());
+
+    // Create the plugin object dynamically so we can set its src. The plugin
+    // element is sized to fill the entire window and is set to be fixed
+    // positioning, acting as a viewport. The plugin renders into this viewport
+    // according to the scroll position of the window.
+    /** @private {!HTMLEmbedElement} */
+    this.plugin_ =
+        /** @type {!HTMLEmbedElement} */ (document.createElement('embed'));
+
+    // NOTE: The plugin's 'id' field must be set to 'plugin' since
+    // chrome/renderer/printing/print_render_frame_helper.cc actually
+    // references it.
+    this.plugin_.id = 'plugin';
+    this.plugin_.type = 'application/x-google-chrome-pdf';
+
+    // Handle scripting messages from outside the extension that wish to
+    // interact with it. We also send a message indicating that extension has
+    // loaded and is ready to receive messages.
+    window.addEventListener('message', message => {
+      this.handleScriptingMessage(/** @type {!MessageObject} */ (message));
+    }, false);
+
+    this.plugin_.setAttribute('src', this.originalUrl_);
     this.plugin_.setAttribute(
-        'top-level-url', this.browserApi_.getStreamInfo().tabUrl);
-  } else {
-    this.plugin_.setAttribute('full-frame', '');
-  }
+        'stream-url', this.browserApi_.getStreamInfo().streamUrl);
+    let headers = '';
+    for (const header in this.browserApi_.getStreamInfo().responseHeaders) {
+      headers += header + ': ' +
+          this.browserApi_.getStreamInfo().responseHeaders[header] + '\n';
+    }
+    this.plugin_.setAttribute('headers', headers);
 
-  $('content').appendChild(this.plugin_);
-
-  this.pluginController_ =
-      new PluginController(this.plugin_, this, this.viewport_);
-  this.inkController_ = new InkController(this, this.viewport_);
-  this.currentController_ = this.pluginController_;
-
-  // Setup the button event listeners.
-  this.zoomToolbar_ = $('zoom-toolbar');
-  this.zoomToolbar_.setIsPrintPreview(this.isPrintPreview_);
-  this.zoomToolbar_.addEventListener(
-      'fit-to-changed', e => this.fitToChanged_(e));
-  this.zoomToolbar_.addEventListener('zoom-in', () => this.viewport_.zoomIn());
-  this.zoomToolbar_.addEventListener(
-      'zoom-out', () => this.viewport_.zoomOut());
-
-  this.gestureDetector_ = new GestureDetector($('content'));
-  this.gestureDetector_.addEventListener(
-      'pinchstart', e => this.onPinchStart_(e));
-  this.sentPinchEvent_ = false;
-  this.gestureDetector_.addEventListener(
-      'pinchupdate', e => this.onPinchUpdate_(e));
-  this.gestureDetector_.addEventListener('pinchend', e => this.onPinchEnd_(e));
-
-  if (toolbarEnabled) {
-    this.toolbar_ = $('toolbar');
-    this.toolbar_.hidden = false;
-    this.toolbar_.addEventListener('save', () => this.save());
-    this.toolbar_.addEventListener('print', () => this.print());
-    this.toolbar_.addEventListener(
-        'undo', () => this.currentController_.undo());
-    this.toolbar_.addEventListener(
-        'redo', () => this.currentController_.redo());
-    this.toolbar_.addEventListener(
-        'rotate-right', () => this.rotateClockwise());
-    this.toolbar_.addEventListener(
-        'annotation-mode-toggled', e => this.annotationModeToggled_(e));
-    this.toolbar_.addEventListener(
-        'annotation-tool-changed',
-        e => this.inkController_.setAnnotationTool(e.detail.value));
-
-    this.toolbar_.docTitle = getFilenameFromURL(this.originalUrl_);
-  }
+    this.plugin_.setAttribute('background-color', PDFViewer.BACKGROUND_COLOR);
+    this.plugin_.setAttribute('top-toolbar-height', topToolbarHeight);
+    this.plugin_.setAttribute('javascript', this.javascript_);
 
-  document.body.addEventListener('change-page', e => {
-    this.viewport_.goToPage(e.detail.page);
-    if (e.detail.origin == 'bookmark') {
-      PDFMetrics.record(PDFMetrics.UserAction.FOLLOW_BOOKMARK);
-    } else if (e.detail.origin == 'pageselector') {
-      PDFMetrics.record(PDFMetrics.UserAction.PAGE_SELECTOR_NAVIGATE);
+    if (this.browserApi_.getStreamInfo().embedded) {
+      this.plugin_.setAttribute(
+          'top-level-url', this.browserApi_.getStreamInfo().tabUrl);
+    } else {
+      this.plugin_.setAttribute('full-frame', '');
     }
-  });
-
-  document.body.addEventListener('change-page-and-xy', e => {
-    const point = this.viewport_.convertPageToScreen(e.detail.page, e.detail);
-    this.goToPageAndXY_(e.detail.origin, e.detail.page, point);
-  });
-
-  document.body.addEventListener('navigate', e => {
-    const disposition = e.detail.newtab ?
-        PdfNavigator.WindowOpenDisposition.NEW_BACKGROUND_TAB :
-        PdfNavigator.WindowOpenDisposition.CURRENT_TAB;
-    this.navigator_.navigate(e.detail.uri, disposition);
-  });
-
-  document.body.addEventListener('dropdown-opened', e => {
-    if (e.detail == 'bookmarks') {
-      PDFMetrics.record(PDFMetrics.UserAction.OPEN_BOOKMARKS_PANEL);
+
+    $('content').appendChild(this.plugin_);
+
+    /** @private {!PluginController} */
+    this.pluginController_ = new PluginController(
+        this.plugin_, this.viewport_, () => this.isUserInitiatedEvent_,
+        () => this.loaded);
+    this.tracker_.add(
+        this.pluginController_.getEventTarget(), 'plugin-message',
+        e => this.handlePluginMessage_(e));
+
+    /** @private {!InkController} */
+    this.inkController_ = new InkController(this.viewport_);
+    this.tracker_.add(
+        this.inkController_.getEventTarget(), 'stroke-added',
+        () => chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(true));
+    this.tracker_.add(
+        this.inkController_.getEventTarget(), 'set-annotation-undo-state',
+        e => this.setAnnotationUndoState_(e));
+
+    /** @private {!ContentController} */
+    this.currentController_ = this.pluginController_;
+
+    // Setup the button event listeners.
+    /** @private {!ViewerZoomToolbarElement} */
+    this.zoomToolbar_ =
+        /** @type {!ViewerZoomToolbarElement} */ ($('zoom-toolbar'));
+    this.zoomToolbar_.setIsPrintPreview(this.isPrintPreview_);
+    this.zoomToolbar_.addEventListener(
+        'fit-to-changed',
+        e => this.fitToChanged_(
+            /** @type {!CustomEvent<FitToChangedEvent>}} */ (e)));
+    this.zoomToolbar_.addEventListener(
+        'zoom-in', () => this.viewport_.zoomIn());
+    this.zoomToolbar_.addEventListener(
+        'zoom-out', () => this.viewport_.zoomOut());
+
+    /** @private {!GestureDetector} */
+    this.gestureDetector_ = new GestureDetector(assert($('content')));
+    this.gestureDetector_.addEventListener(
+        'pinchstart', e => this.onPinchStart_(e));
+    this.sentPinchEvent_ = false;
+    this.gestureDetector_.addEventListener(
+        'pinchupdate', e => this.onPinchUpdate_(e));
+    this.gestureDetector_.addEventListener(
+        'pinchend', e => this.onPinchEnd_(e));
+
+    /** @private {?ViewerPdfToolbarElement} */
+    this.toolbar_ = null;
+    if (toolbarEnabled) {
+      this.toolbar_ = /** @type {!ViewerPdfToolbarElement} */ ($('toolbar'));
+      this.toolbar_.hidden = false;
+      this.toolbar_.addEventListener('save', () => this.save_());
+      this.toolbar_.addEventListener('print', () => this.print_());
+      this.toolbar_.addEventListener(
+          'undo', () => this.currentController_.undo());
+      this.toolbar_.addEventListener(
+          'redo', () => this.currentController_.redo());
+      this.toolbar_.addEventListener(
+          'rotate-right', () => this.rotateClockwise_());
+      this.toolbar_.addEventListener('annotation-mode-toggled', e => {
+        this.annotationModeToggled_(
+            /** @type {!CustomEvent<{value: boolean}>} */ (e));
+      });
+      this.toolbar_.addEventListener(
+          'annotation-tool-changed',
+          e => this.inkController_.setAnnotationTool(e.detail.value));
+
+      this.toolbar_.docTitle = getFilenameFromURL(this.originalUrl_);
+    }
+
+    document.body.addEventListener('change-page', e => {
+      this.viewport_.goToPage(e.detail.page);
+      if (e.detail.origin == 'bookmark') {
+        PDFMetrics.record(PDFMetrics.UserAction.FOLLOW_BOOKMARK);
+      } else if (e.detail.origin == 'pageselector') {
+        PDFMetrics.record(PDFMetrics.UserAction.PAGE_SELECTOR_NAVIGATE);
+      }
+    });
+
+    document.body.addEventListener('change-zoom', e => {
+      this.viewport_.setZoom(e.detail.zoom);
+    });
+
+    document.body.addEventListener('change-page-and-xy', e => {
+      const point = this.viewport_.convertPageToScreen(e.detail.page, e.detail);
+      this.goToPageAndXY_(e.detail.origin, e.detail.page, point);
+    });
+
+    document.body.addEventListener('navigate', e => {
+      const disposition = e.detail.newtab ?
+          PdfNavigator.WindowOpenDisposition.NEW_BACKGROUND_TAB :
+          PdfNavigator.WindowOpenDisposition.CURRENT_TAB;
+      this.navigator_.navigate(e.detail.uri, disposition);
+    });
+
+    document.body.addEventListener('dropdown-opened', e => {
+      if (e.detail == 'bookmarks') {
+        PDFMetrics.record(PDFMetrics.UserAction.OPEN_BOOKMARKS_PANEL);
+      }
+    });
+
+    /** @private {!ToolbarManager} */
+    this.toolbarManager_ =
+        new ToolbarManager(window, this.toolbar_, this.zoomToolbar_);
+
+    // Set up the ZoomManager.
+    /** @private {!ZoomManager} */
+    this.zoomManager_ = ZoomManager.create(
+        this.browserApi_.getZoomBehavior(), () => this.viewport_.getZoom(),
+        zoom => this.browserApi_.setZoom(zoom),
+        this.browserApi_.getInitialZoom());
+    this.viewport_.setZoomManager(this.zoomManager_);
+    this.browserApi_.addZoomEventListener(
+        zoom => this.zoomManager_.onBrowserZoomChange(zoom));
+
+    // Setup the keyboard event listener.
+    document.addEventListener(
+        'keydown',
+        e => this.handleKeyEvent_(/** @type {!KeyboardEvent} */ (e)));
+    document.addEventListener('mousemove', e => this.handleMouseEvent_(e));
+    document.addEventListener('mouseout', e => this.handleMouseEvent_(e));
+    document.addEventListener(
+        'contextmenu', e => this.handleContextMenuEvent_(e));
+
+    const tabId = this.browserApi_.getStreamInfo().tabId;
+    /** @private {!PdfNavigator} */
+    this.navigator_ = new PdfNavigator(
+        this.originalUrl_, this.viewport_, this.paramsParser_,
+        new NavigatorDelegate(tabId));
+
+    /** @private {!ViewportScroller} */
+    this.viewportScroller_ =
+        new ViewportScroller(this.viewport_, this.plugin_, window);
+
+    /** @private {!Array<!Bookmark>} */
+    this.bookmarks_;
+
+    /** @private {!Point} */
+    this.lastViewportPosition_;
+
+    /** @private {boolean} */
+    this.reverseZoomToolbar_;
+
+    /** @private {boolean} */
+    this.inPrintPreviewMode_;
+
+    /** @private {boolean} */
+    this.dark_;
+
+    /** @private {!DocumentDimensionsMessageData} */
+    this.documentDimensions_;
+
+    // Request translated strings.
+    chrome.resourcesPrivate.getStrings(
+        chrome.resourcesPrivate.Component.PDF,
+        strings => this.handleStrings_(strings));
+
+    // Listen for save commands from the browser.
+    if (chrome.mimeHandlerPrivate && chrome.mimeHandlerPrivate.onSave) {
+      chrome.mimeHandlerPrivate.onSave.addListener(url => this.onSave_(url));
     }
-  });
-
-  this.toolbarManager_ =
-      new ToolbarManager(window, this.toolbar_, this.zoomToolbar_);
-
-  // Set up the ZoomManager.
-  this.zoomManager_ = ZoomManager.create(
-      this.browserApi_.getZoomBehavior(), () => this.viewport_.getZoom(),
-      zoom => this.browserApi_.setZoom(zoom),
-      this.browserApi_.getInitialZoom());
-  this.viewport_.setZoomManager(this.zoomManager_);
-  this.browserApi_.addZoomEventListener(
-      zoom => this.zoomManager_.onBrowserZoomChange(zoom));
-
-  // Setup the keyboard event listener.
-  document.addEventListener('keydown', e => this.handleKeyEvent_(e));
-  document.addEventListener('mousemove', e => this.handleMouseEvent_(e));
-  document.addEventListener('mouseout', e => this.handleMouseEvent_(e));
-  document.addEventListener(
-      'contextmenu', e => this.handleContextMenuEvent_(e));
-
-  const tabId = this.browserApi_.getStreamInfo().tabId;
-  this.navigator_ = new PdfNavigator(
-      this.originalUrl_, this.viewport_, this.paramsParser_,
-      new NavigatorDelegate(tabId));
-  this.viewportScroller_ =
-      new ViewportScroller(this.viewport_, this.plugin_, window);
-
-  // Request translated strings.
-  chrome.resourcesPrivate.getStrings(
-      'pdf', strings => this.handleStrings_(strings));
-
-  // Listen for save commands from the browser.
-  if (chrome.mimeHandlerPrivate && chrome.mimeHandlerPrivate.onSave) {
-    chrome.mimeHandlerPrivate.onSave.addListener(url => this.onSave(url));
   }
-}
 
-PDFViewer.prototype = {
   /**
    * Handle key events. These may come from the user directly or via the
    * scripting API.
-   *
-   * @param {KeyboardEvent} e the event to handle.
+   * @param {!KeyboardEvent} e the event to handle.
    * @private
    */
-  handleKeyEvent_: function(e) {
+  handleKeyEvent_(e) {
     const position = this.viewport_.position;
     // Certain scroll events may be sent from outside of the extension.
     const fromScriptingAPI = e.fromScriptingAPI;
@@ -357,7 +459,7 @@ PDFViewer.prototype = {
       return;
     }
 
-    this.toolbarManager_.hideToolbarsAfterTimeout(e);
+    this.toolbarManager_.hideToolbarsAfterTimeout();
 
     const pageUpHandler = () => {
       // Go to the previous page if we are fit-to-page or fit-to-height.
@@ -366,8 +468,8 @@ PDFViewer.prototype = {
         // Since we do the movement of the page.
         e.preventDefault();
       } else if (fromScriptingAPI) {
-        position.y -= this.viewport.size.height;
-        this.viewport.position = position;
+        position.y -= this.viewport_.size.height;
+        this.viewport_.position = position;
       }
     };
     const pageDownHandler = () => {
@@ -377,8 +479,8 @@ PDFViewer.prototype = {
         // Since we do the movement of the page.
         e.preventDefault();
       } else if (fromScriptingAPI) {
-        position.y += this.viewport.size.height;
-        this.viewport.position = position;
+        position.y += this.viewport_.size.height;
+        this.viewport_.position = position;
       }
     };
 
@@ -416,14 +518,14 @@ PDFViewer.prototype = {
             e.preventDefault();
           } else if (fromScriptingAPI) {
             position.x -= Viewport.SCROLL_INCREMENT;
-            this.viewport.position = position;
+            this.viewport_.position = position;
           }
         }
         return;
       case 38:  // Up arrow key.
         if (fromScriptingAPI) {
           position.y -= Viewport.SCROLL_INCREMENT;
-          this.viewport.position = position;
+          this.viewport_.position = position;
         }
         return;
       case 39:  // Right arrow key.
@@ -437,19 +539,19 @@ PDFViewer.prototype = {
             e.preventDefault();
           } else if (fromScriptingAPI) {
             position.x += Viewport.SCROLL_INCREMENT;
-            this.viewport.position = position;
+            this.viewport_.position = position;
           }
         }
         return;
       case 40:  // Down arrow key.
         if (fromScriptingAPI) {
           position.y += Viewport.SCROLL_INCREMENT;
-          this.viewport.position = position;
+          this.viewport_.position = position;
         }
         return;
       case 65:  // 'a' key.
         if (e.ctrlKey || e.metaKey) {
-          this.pluginController_.postMessage({type: 'selectAll'});
+          this.pluginController_.selectAll();
           // Since we do selection ourselves.
           e.preventDefault();
         }
@@ -462,7 +564,7 @@ PDFViewer.prototype = {
         return;
       case 219:  // Left bracket key.
         if (e.ctrlKey) {
-          this.rotateCounterclockwise();
+          this.rotateCounterclockwise_();
         }
         return;
       case 220:  // Backslash key.
@@ -472,7 +574,7 @@ PDFViewer.prototype = {
         return;
       case 221:  // Right bracket key.
         if (e.ctrlKey) {
-          this.rotateClockwise();
+          this.rotateClockwise_();
         }
         return;
     }
@@ -487,42 +589,49 @@ PDFViewer.prototype = {
         this.toolbarManager_.showToolbars();
       }
     }
-  },
+  }
 
-  handleMouseEvent_: function(e) {
+  handleMouseEvent_(e) {
     if (e.type == 'mousemove') {
       this.toolbarManager_.handleMouseMove(e);
     } else if (e.type == 'mouseout') {
       this.toolbarManager_.hideToolbarsForMouseOut();
     }
-  },
+  }
 
-  handleContextMenuEvent_: function(e) {
+  /**
+   * @param {!Event} e The context menu event
+   * @private
+   */
+  handleContextMenuEvent_(e) {
     // Stop Chrome from popping up the context menu on long press. We need to
     // make sure the start event did not have 2 touches because we don't want
     // to block two finger tap opening the context menu. We check for
     // firesTouchEvents in order to not block the context menu on right click.
-    if (e.sourceCapabilities.firesTouchEvents &&
+    const capabilities =
+        /** @type {{ sourceCapabilities: Object }} */ (e).sourceCapabilities;
+    if (capabilities.firesTouchEvents &&
         !this.gestureDetector_.wasTwoFingerTouch()) {
       e.preventDefault();
     }
-  },
+  }
 
   /**
    * Handles the annotation mode being toggled on or off.
-   *
    * @param {!CustomEvent<{value: boolean}>} e
    * @private
    */
-  annotationModeToggled_: async function(e) {
+  async annotationModeToggled_(e) {
     const annotationMode = e.detail.value;
     if (annotationMode) {
       // Enter annotation mode.
       assert(this.currentController_ == this.pluginController_);
       // TODO(dstockwell): set plugin read-only, begin transition
-      this.updateProgress(0);
+      this.updateProgress_(0);
       // TODO(dstockwell): handle save failure
-      const result = await this.pluginController_.save(true);
+      const saveResult = await this.pluginController_.save(true);
+      // Data always exists when save is called with requireResult = true.
+      const result = /** @type {!RequiredSaveResult} */ (saveResult);
       if (result.hasUnsavedChanges) {
         assert(!loadTimeData.getBoolean('pdfFormSaveEnabled'));
         try {
@@ -530,25 +639,26 @@ PDFViewer.prototype = {
         } catch (e) {
           // The user aborted entering annotation mode. Revert to the plugin.
           this.toolbar_.annotationMode = false;
-          this.updateProgress(100);
+          this.updateProgress_(100);
           return;
         }
       }
       PDFMetrics.record(PDFMetrics.UserAction.ENTER_ANNOTATION_MODE);
       this.hasEnteredAnnotationMode_ = true;
       // TODO(dstockwell): feed real progress data from the Ink component
-      this.updateProgress(50);
+      this.updateProgress_(50);
       await this.inkController_.load(result.fileName, result.dataToSave);
-      this.inkController_.setAnnotationTool(this.toolbar_.annotationTool);
+      this.inkController_.setAnnotationTool(
+          assert(this.toolbar_.annotationTool));
       this.currentController_ = this.inkController_;
       this.pluginController_.unload();
-      this.updateProgress(100);
+      this.updateProgress_(100);
     } else {
       // Exit annotation mode.
       PDFMetrics.record(PDFMetrics.UserAction.EXIT_ANNOTATION_MODE);
       assert(this.currentController_ == this.inkController_);
       // TODO(dstockwell): set ink read-only, begin transition
-      this.updateProgress(0);
+      this.updateProgress_(0);
       // This runs separately to allow other consumers of `loaded` to queue
       // up after this task.
       this.loaded.then(() => {
@@ -556,36 +666,33 @@ PDFViewer.prototype = {
         this.inkController_.unload();
       });
       // TODO(dstockwell): handle save failure
-      const result = await this.inkController_.save(true);
+      const saveResult = await this.inkController_.save(true);
+      // Data always exists when save is called with requireResult = true.
+      const result = /** @type {!RequiredSaveResult} */ (saveResult);
       await this.pluginController_.load(result.fileName, result.dataToSave);
       // Ensure the plugin gets the initial viewport.
       this.pluginController_.afterZoom();
     }
-  },
+  }
 
   /**
    * Exits annotation mode if active.
-   *
    * @return {Promise<void>}
    */
-  exitAnnotationMode_: async function() {
+  async exitAnnotationMode_() {
     if (!this.toolbar_.annotationMode) {
       return;
     }
     this.toolbar_.toggleAnnotation();
     await this.loaded;
-  },
+  }
 
   /**
    * Request to change the viewport fitting type.
-   *
-   * @param {!CustomEvent<{
-   *     fittingType: FittingType,
-   *     userInitiated: boolean
-   * }>} e
+   * @param {!CustomEvent<FitToChangedEvent>} e
    * @private
    */
-  fitToChanged_: function(e) {
+  fitToChanged_(e) {
     if (e.detail.fittingType == FittingType.FIT_TO_PAGE) {
       this.viewport_.fitToPage();
       this.toolbarManager_.forceHideTopToolbar();
@@ -599,15 +706,14 @@ PDFViewer.prototype = {
     if (e.detail.userInitiated) {
       PDFMetrics.recordFitTo(e.detail.fittingType);
     }
-  },
+  }
 
   /**
    * Sends a 'documentLoaded' message to the PDFScriptingAPI if the document has
    * finished loading.
-   *
    * @private
    */
-  sendDocumentLoadedMessage_: function() {
+  sendDocumentLoadedMessage_() {
     if (this.loadState_ == LoadState.LOADING) {
       return;
     }
@@ -616,17 +722,16 @@ PDFViewer.prototype = {
     }
     this.sendScriptingMessage_(
         {type: 'documentLoaded', load_state: this.loadState_});
-  },
+  }
 
   /**
    * Handle open pdf parameters. This function updates the viewport as per
    * the parameters mentioned in the url while opening pdf. The order is
    * important as later actions can override the effects of previous actions.
-   *
    * @param {Object} params The open params passed in the URL.
    * @private
    */
-  handleURLParams_: function(params) {
+  handleURLParams_(params) {
     if (params.zoom) {
       this.viewport_.setZoom(params.zoom);
     }
@@ -654,32 +759,42 @@ PDFViewer.prototype = {
       }
       this.isUserInitiatedEvent_ = true;
     }
-  },
+  }
 
   /**
    * Moves the viewport to a point in a page. Called back after a
    * 'transformPagePointReply' is returned from the plugin.
-   *
    * @param {string} origin Identifier for the caller for logging purposes.
    * @param {number} page The index of the page to go to. zero-based.
-   * @param {Object} message Message received from the plugin containing the
+   * @param {Point} message Message received from the plugin containing the
    *     x and y to navigate to in screen coordinates.
    * @private
    */
-  goToPageAndXY_: function(origin, page, message) {
+  goToPageAndXY_(origin, page, message) {
     this.viewport_.goToPageAndXY(page, message.x, message.y);
     if (origin == 'bookmark') {
       PDFMetrics.record(PDFMetrics.UserAction.FOLLOW_BOOKMARK);
     }
-  },
+  }
 
   /**
-   * @return {Promise} Resolved when the load state reaches LOADED,
-   *     rejects on FAILED.
+   * @return {?Promise} Resolved when the load state reaches LOADED,
+   * rejects on FAILED. Returns null if no promise has been created, which
+   * is the case for initial load of the PDF.
    */
   get loaded() {
-    return this.loaded_.promise;
-  },
+    return this.loaded_ ? this.loaded_.promise : null;
+  }
+
+  /** @return {!Viewport} The viewport. Used for testing. */
+  get viewport() {
+    return this.viewport_;
+  }
+
+  /** @return {!Array<!Bookmark>} The bookmarks. Used for testing. */
+  get bookmarks() {
+    return this.bookmarks_;
+  }
 
   /**
    * Updates the load state and triggers completion of the `loaded`
@@ -691,26 +806,29 @@ PDFViewer.prototype = {
     if (this.loadState_ == loadState) {
       return;
     }
+    assert(
+        loadState == LoadState.LOADING || this.loadState_ == LoadState.LOADING);
+    this.loadState_ = loadState;
+    if (!this.initialLoadComplete_) {
+      this.initialLoadComplete_ = true;
+      return;
+    }
     if (loadState == LoadState.SUCCESS) {
-      assert(this.loadState_ == LoadState.LOADING);
       this.loaded_.resolve();
     } else if (loadState == LoadState.FAILED) {
-      assert(this.loadState_ == LoadState.LOADING);
       this.loaded_.reject();
     } else {
-      assert(loadState == LoadState.LOADING);
       this.loaded_ = new PromiseResolver();
     }
-    this.loadState_ = loadState;
-  },
+  }
 
   /**
    * Update the loading progress of the document in response to a progress
    * message being received from the content controller.
-   *
    * @param {number} progress the progress as a percentage.
+   * @private
    */
-  updateProgress: function(progress) {
+  updateProgress_(progress) {
     if (this.toolbar_) {
       this.toolbar_.loadProgress = progress;
     }
@@ -743,28 +861,26 @@ PDFViewer.prototype = {
     } else {
       this.setLoadState_(LoadState.LOADING);
     }
-  },
+  }
 
   /** @private */
-  sendBackgroundColorForPrintPreview_: function() {
-    this.pluginController_.postMessage({
-      type: 'backgroundColorChanged',
-      backgroundColor: this.dark_ ?
-          PDFViewer.PRINT_PREVIEW_DARK_BACKGROUND_COLOR :
-          PDFViewer.PRINT_PREVIEW_BACKGROUND_COLOR,
-    });
-  },
+  sendBackgroundColorForPrintPreview_() {
+    this.pluginController_.backgroundColorChanged(
+        this.dark_ ? PDFViewer.PRINT_PREVIEW_DARK_BACKGROUND_COLOR :
+                     PDFViewer.PRINT_PREVIEW_BACKGROUND_COLOR);
+  }
 
   /**
    * Load a dictionary of translated strings into the UI. Used as a callback for
    * chrome.resourcesPrivate.
-   *
    * @param {Object} strings Dictionary of translated strings
    * @private
    */
-  handleStrings_: function(strings) {
-    document.documentElement.dir = strings.textdirection;
-    document.documentElement.lang = strings.language;
+  handleStrings_(strings) {
+    const stringsDictionary =
+        /** @type {{ textdirection: string, language: string }} */ (strings);
+    document.documentElement.dir = stringsDictionary.textdirection;
+    document.documentElement.lang = stringsDictionary.language;
 
     loadTimeData.data = strings;
     const isNewPrintPreview = this.isPrintPreview_ &&
@@ -786,38 +902,34 @@ PDFViewer.prototype = {
     if ($('form-warning')) {
       $('form-warning').strings = strings;
     }
-  },
+  }
 
   /**
    * An event handler for handling password-submitted events. These are fired
    * when an event is entered into the password screen.
-   *
-   * @param {Object} event a password-submitted event.
+   * @param {!CustomEvent<{password: string}>} event a password-submitted event.
    * @private
    */
-  onPasswordSubmitted_: function(event) {
-    this.pluginController_.postMessage(
-        {type: 'getPasswordComplete', password: event.detail.password});
-  },
+  onPasswordSubmitted_(event) {
+    this.pluginController_.getPasswordComplete(event.detail.password);
+  }
 
   /**
    * A callback that sets |isUserInitiatedEvent_| to |userInitiated|.
-   *
    * @param {boolean} userInitiated The value to set |isUserInitiatedEvent_| to.
    * @private
    */
-  setUserInitiated_: function(userInitiated) {
+  setUserInitiated_(userInitiated) {
     assert(this.isUserInitiatedEvent_ != userInitiated);
     this.isUserInitiatedEvent_ = userInitiated;
-  },
+  }
 
   /**
    * A callback that's called when an update to a pinch zoom is detected.
-   *
    * @param {!Object} e the pinch event.
    * @private
    */
-  onPinchUpdate_: function(e) {
+  onPinchUpdate_(e) {
     // Throttle number of pinch events to one per frame.
     if (!this.sentPinchEvent_) {
       this.sentPinchEvent_ = true;
@@ -826,42 +938,39 @@ PDFViewer.prototype = {
         this.viewport_.pinchZoom(e);
       });
     }
-  },
+  }
 
   /**
    * A callback that's called when the end of a pinch zoom is detected.
-   *
    * @param {!Object} e the pinch event.
    * @private
    */
-  onPinchEnd_: function(e) {
+  onPinchEnd_(e) {
     // Using rAF for pinch end prevents pinch updates scheduled by rAF getting
     // sent after the pinch end.
     window.requestAnimationFrame(() => {
       this.viewport_.pinchZoomEnd(e);
     });
-  },
+  }
 
   /**
    * A callback that's called when the start of a pinch zoom is detected.
-   *
    * @param {!Object} e the pinch event.
    * @private
    */
-  onPinchStart_: function(e) {
+  onPinchStart_(e) {
     // We also use rAF for pinch start, so that if there is a pinch end event
     // scheduled by rAF, this pinch start will be sent after.
     window.requestAnimationFrame(() => {
       this.viewport_.pinchZoomStart(e);
     });
-  },
+  }
 
   /**
    * A callback that's called after the viewport changes.
-   *
    * @private
    */
-  viewportChanged_: function() {
+  viewportChanged_() {
     if (!this.documentDimensions_) {
       return;
     }
@@ -900,9 +1009,10 @@ PDFViewer.prototype = {
 
     // TODO(raymes): Give pageIndicator_ the same API as toolbar_.
     if (this.pageIndicator_) {
+      const lastIndex = this.pageIndicator_.index;
       this.pageIndicator_.index = visiblePage;
       if (this.documentDimensions_.pageDimensions.length > 1 &&
-          hasScrollbars.vertical) {
+          hasScrollbars.vertical && lastIndex !== undefined) {
         this.pageIndicator_.style.visibility = 'visible';
       } else {
         this.pageIndicator_.style.visibility = 'hidden';
@@ -921,16 +1031,15 @@ PDFViewer.prototype = {
       viewportWidth: size.width,
       viewportHeight: size.height
     });
-  },
+  }
 
   /**
    * Handle a scripting message from outside the extension (typically sent by
    * PDFScriptingAPI in a page containing the extension) to interact with the
    * plugin.
-   *
-   * @param {MessageObject} message the message to handle.
+   * @param {!MessageObject} message The message to handle.
    */
-  handleScriptingMessage: function(message) {
+  handleScriptingMessage(message) {
     if (this.parentWindow_ != message.source) {
       this.parentWindow_ = message.source;
       this.parentOrigin_ = message.origin;
@@ -953,30 +1062,38 @@ PDFViewer.prototype = {
 
     switch (message.data.type.toString()) {
       case 'getSelectedText':
+        this.pluginController_.getSelectedText();
+        break;
       case 'print':
+        this.pluginController_.print();
+        break;
       case 'selectAll':
-        this.pluginController_.postMessage(message.data);
+        this.pluginController_.selectAll();
         break;
     }
-  },
+  }
 
   /**
    * Handle scripting messages specific to print preview.
-   *
-   * @param {MessageObject} message the message to handle.
+   * @param {!MessageObject} message the message to handle.
    * @return {boolean} true if the message was handled, false otherwise.
    * @private
    */
-  handlePrintPreviewScriptingMessage_: function(message) {
+  handlePrintPreviewScriptingMessage_(message) {
     if (!this.isPrintPreview_) {
       return false;
     }
 
-    switch (message.data.type.toString()) {
+    let messageData = message.data;
+    switch (messageData.type.toString()) {
       case 'loadPreviewPage':
-        this.pluginController_.postMessage(message.data);
+        messageData =
+            /** @type {{ url:  string, index: number }} */ (messageData);
+        this.pluginController_.loadPreviewPage(
+            messageData.url, messageData.index);
         return true;
       case 'resetPrintPreviewMode':
+        messageData = /** @type {!PrintPreviewParams} */ (messageData);
         this.setLoadState_(LoadState.LOADING);
         if (!this.inPrintPreviewMode_) {
           this.inPrintPreviewMode_ = true;
@@ -999,49 +1116,42 @@ PDFViewer.prototype = {
           saveButton.parentNode.removeChild(saveButton);
         }
 
-        this.pageIndicator_.pageLabels = message.data.pageNumbers;
+        this.pageIndicator_.pageLabels = messageData.pageNumbers;
 
-        this.pluginController_.postMessage({
-          type: 'resetPrintPreviewMode',
-          url: message.data.url,
-          grayscale: message.data.grayscale,
-          // If the PDF isn't modifiable we send 0 as the page count so that no
-          // blank placeholder pages get appended to the PDF.
-          pageCount:
-              (message.data.modifiable ? message.data.pageNumbers.length : 0)
-        });
+        this.pluginController_.resetPrintPreviewMode(messageData);
         return true;
       case 'sendKeyEvent':
-        this.handleKeyEvent_(DeserializeKeyEvent(message.data.keyEvent));
+        this.handleKeyEvent_(/** @type {!KeyboardEvent} */ (DeserializeKeyEvent(
+            /** @type {{ keyEvent: Object }} */ (message.data).keyEvent)));
         return true;
       case 'hideToolbars':
         this.toolbarManager_.resetKeyboardNavigationAndHideToolbars();
         return true;
       case 'darkModeChanged':
-        this.dark_ = message.data.darkMode;
+        this.dark_ = /** @type {{darkMode: boolean}} */ (message.data).darkMode;
         if (this.isPrintPreview_) {
           this.sendBackgroundColorForPrintPreview_();
         }
         return true;
       case 'scrollPosition':
         const position = this.viewport_.position;
-        position.y += message.data.y;
-        position.x += message.data.x;
-        this.viewport.position = position;
+        messageData = /** @type {{ x: number, y: number }} */ (message.data);
+        position.y += messageData.y;
+        position.x += messageData.x;
+        this.viewport_.position = position;
         return true;
     }
 
     return false;
-  },
+  }
 
   /**
    * Send a scripting message outside the extension (typically to
    * PDFScriptingAPI in a page containing the extension).
-   *
    * @param {Object} message the message to send.
    * @private
    */
-  sendScriptingMessage_: function(message) {
+  sendScriptingMessage_(message) {
     if (this.parentWindow_ && this.parentOrigin_) {
       let targetOrigin;
       // Only send data back to the embedder if it is from the same origin,
@@ -1057,34 +1167,73 @@ PDFViewer.prototype = {
       }
       this.parentWindow_.postMessage(message, targetOrigin);
     }
-  },
-
-  /**
-   * @type {Viewport} the viewport of the PDF viewer.
-   */
-  get viewport() {
-    return this.viewport_;
-  },
+  }
 
   /**
-   * Each bookmark is an Object containing a:
-   * - title
-   * - page (optional)
-   * - array of children (themselves bookmarks)
-   *
-   * @type {Array} the top-level bookmarks of the PDF.
+   * @param {!CustomEvent<MessageData>} e
+   * @private
    */
-  get bookmarks() {
-    return this.bookmarks_;
-  },
+  handlePluginMessage_(e) {
+    const data = e.detail;
+    switch (data.type.toString()) {
+      case 'beep':
+        this.handleBeep_();
+        return;
+      case 'documentDimensions':
+        this.setDocumentDimensions_(
+            /** @type {!DocumentDimensionsMessageData} */ (data));
+        return;
+      case 'getPassword':
+        this.handlePasswordRequest_();
+        return;
+      case 'getSelectedTextReply':
+        this.handleSelectedTextReply_(
+            /** @type {{ selectedText: string }} */ (data).selectedText);
+        return;
+      case 'loadProgress':
+        this.updateProgress_(
+            /** @type {{ progress: number }} */ (data).progress);
+        return;
+      case 'navigate':
+        const navigateData = /** @type {!NavigateMessageData} */ (data);
+        this.handleNavigate_(navigateData.url, navigateData.disposition);
+        return;
+      case 'navigateToDestination':
+        const destinationData = /** @type {!DestinationMessageData} */ (data);
+        this.handleNavigateToDestination_(
+            destinationData.page, destinationData.x, destinationData.y,
+            destinationData.zoom);
+        return;
+      case 'printPreviewLoaded':
+        this.handlePrintPreviewLoaded_();
+        return;
+      case 'metadata':
+        const metadata = /** @type {!MetadataMessageData} */ (data);
+        this.setDocumentMetadata_(
+            metadata.title, metadata.bookmarks, metadata.canSerializeDocument);
+        return;
+      case 'setIsSelecting':
+        this.setIsSelecting_(
+            /** @type {{ isSelecting: boolean }} */ (data).isSelecting);
+        return;
+      case 'getNamedDestinationReply':
+        this.paramsParser_.onNamedDestinationReceived(
+            /** @type {{ pageNumber: number }} */ (data).pageNumber);
+        return;
+      case 'formFocusChange':
+        this.isFormFieldFocused_ =
+            /** @type {{ focused: boolean }} */ (data).focused;
+        return;
+    }
+    assertNotReached('Unknown message type received: ' + data.type);
+  }
 
   /**
    * Sets document dimensions from the current controller.
-   *
-   * @param {{height: number, width: number, pageDimensions: Array}}
-   *     documentDimensions
+   * @param {!DocumentDimensionsMessageData} documentDimensions
+   * @private
    */
-  setDocumentDimensions: function(documentDimensions) {
+  setDocumentDimensions_(documentDimensions) {
     this.documentDimensions_ = documentDimensions;
     this.isUserInitiatedEvent_ = false;
     this.viewport_.setDocumentDimensions(this.documentDimensions_);
@@ -1098,20 +1247,22 @@ PDFViewer.prototype = {
     if (this.toolbar_) {
       this.toolbar_.docLength = this.documentDimensions_.pageDimensions.length;
     }
-  },
+  }
 
   /**
    * Handles a beep request from the current controller.
+   * @private
    */
-  handleBeep: function() {
+  handleBeep_() {
     // Beeps are annoying, so just track count for now.
     this.beepCount_ += 1;
-  },
+  }
 
   /**
    * Handles a password request from the current controller.
+   * @private
    */
-  handlePasswordRequest: function() {
+  handlePasswordRequest_() {
     // If the password screen isn't up, put it up. Otherwise we're
     // responding to an incorrect password so deny it.
     if (!this.passwordScreen_.active) {
@@ -1121,26 +1272,27 @@ PDFViewer.prototype = {
     } else {
       this.passwordScreen_.deny();
     }
-  },
+  }
 
   /**
    * Handles a selected text reply from the current controller.
    * @param {string} selectedText
+   * @private
    */
-  handleSelectedTextReply: function(selectedText) {
+  handleSelectedTextReply_(selectedText) {
     this.sendScriptingMessage_({
       type: 'getSelectedTextReply',
       selectedText: selectedText,
     });
-  },
+  }
 
   /**
    * Handles a navigation request from the current controller.
-   *
    * @param {string} url
-   * @param {string} disposition
+   * @param {!PdfNavigator.WindowOpenDisposition} disposition
+   * @private
    */
-  handleNavigate: function(url, disposition) {
+  handleNavigate_(url, disposition) {
     // If in print preview, always open a new tab.
     if (this.isPrintPreview_) {
       this.navigator_.navigate(
@@ -1148,24 +1300,48 @@ PDFViewer.prototype = {
     } else {
       this.navigator_.navigate(url, disposition);
     }
-  },
+  }
+
+  /**
+   * Handles an internal navigation request to a destination from the current
+   * controller.
+   *
+   * @param {number} page
+   * @param {number} x
+   * @param {number} y
+   * @param {number} zoom
+   * @private
+   */
+  handleNavigateToDestination_(page, x, y, zoom) {
+    if (zoom) {
+      this.viewport_.setZoom(zoom);
+    }
+
+    if (x || y) {
+      this.viewport_.goToPageAndXY(page, x ? x : 0, y ? y : 0);
+    } else {
+      this.viewport_.goToPage(page);
+    }
+  }
 
   /**
    * Handles a notification that print preview has loaded from the
    * current controller.
+   * @private
    */
-  handlePrintPreviewLoaded: function() {
+  handlePrintPreviewLoaded_() {
     this.isPrintPreviewLoadingFinished_ = true;
     this.sendDocumentLoadedMessage_();
-  },
+  }
 
   /**
    * Sets document metadata from the current controller.
    * @param {string} title
-   * @param {Array} bookmarks
+   * @param {!Array<!Bookmark>} bookmarks
    * @param {boolean} canSerializeDocument
+   * @private
    */
-  setDocumentMetadata: function(title, bookmarks, canSerializeDocument) {
+  setDocumentMetadata_(title, bookmarks, canSerializeDocument) {
     if (title) {
       document.title = title;
     } else {
@@ -1174,47 +1350,40 @@ PDFViewer.prototype = {
     this.bookmarks_ = bookmarks;
     if (this.toolbar_) {
       this.toolbar_.docTitle = document.title;
-      this.toolbar_.bookmarks = this.bookmarks;
+      this.toolbar_.bookmarks = this.bookmarks_;
     }
     this.canSerializeDocument_ = canSerializeDocument;
     this.updateAnnotationAvailable_();
-  },
+  }
 
   /**
    * Sets the is selecting flag from the current controller.
    * @param {boolean} isSelecting
+   * @private
    */
-  setIsSelecting: function(isSelecting) {
+  setIsSelecting_(isSelecting) {
     this.viewportScroller_.setEnableScrolling(isSelecting);
-  },
-
-  /**
-   * Sets the form field focused flag from the current controller.
-   * @param {boolean} focused
-   */
-  setIsFormFieldFocused: function(focused) {
-    this.isFormFieldFocused_ = focused;
-  },
+  }
 
   /**
    * An event handler for when the browser tells the PDF Viewer to perform a
    * save.
-   *
    * @param {string} streamUrl unique identifier for a PDF Viewer instance.
    * @private
    */
-  onSave: async function(streamUrl) {
+  async onSave_(streamUrl) {
     if (streamUrl != this.browserApi_.getStreamInfo().streamUrl) {
       return;
     }
 
-    this.save();
-  },
+    this.save_();
+  }
 
   /**
    * Saves the current PDF document to disk.
+   * @private
    */
-  save: async function() {
+  async save_() {
     PDFMetrics.record(PDFMetrics.UserAction.SAVE);
     if (this.hasEnteredAnnotationMode_) {
       PDFMetrics.record(PDFMetrics.UserAction.SAVE_WITH_ANNOTATION);
@@ -1257,17 +1426,19 @@ PDFViewer.prototype = {
 
     // Saving in Annotation mode is destructive: crbug.com/919364
     this.exitAnnotationMode_();
-  },
+  }
 
-  print: async function() {
+  /** @private */
+  async print_() {
     PDFMetrics.record(PDFMetrics.UserAction.PRINT);
     await this.exitAnnotationMode_();
     this.currentController_.print();
-  },
+  }
 
   /**
    * Updates the toolbar's annotation available flag depending on current
    * conditions.
+   * @private
    */
   updateAnnotationAvailable_() {
     if (!this.toolbar_) {
@@ -1284,408 +1455,67 @@ PDFViewer.prototype = {
       annotationAvailable = false;
     }
     this.toolbar_.annotationAvailable = annotationAvailable;
-  },
+  }
 
-  rotateClockwise() {
+  /** @private */
+  rotateClockwise_() {
     PDFMetrics.record(PDFMetrics.UserAction.ROTATE);
     this.viewport_.rotateClockwise(1);
     this.currentController_.rotateClockwise();
     this.updateAnnotationAvailable_();
-  },
+  }
 
-  rotateCounterclockwise() {
+  /** @private */
+  rotateCounterclockwise_() {
     PDFMetrics.record(PDFMetrics.UserAction.ROTATE);
     this.viewport_.rotateClockwise(3);
     this.currentController_.rotateCounterclockwise();
     this.updateAnnotationAvailable_();
-  },
-
-  setHasUnsavedChanges: function() {
-    // Warn the user if they attempt to close the window without saving.
-    chrome.mimeHandlerPrivate.setShowBeforeUnloadDialog(true);
-  },
-
-  /** @param {UndoState} state */
-  setAnnotationUndoState(state) {
-    this.toolbar_.canUndoAnnotation = state.canUndo;
-    this.toolbar_.canRedoAnnotation = state.canRedo;
-  },
-};
-
-/** @abstract */
-class ContentController {
-  constructor() {}
-
-  /**
-   * A callback that's called before the zoom changes.
-   */
-  beforeZoom() {}
-
-  /**
-   * A callback that's called after the zoom changes.
-   */
-  afterZoom() {}
-
-  /**
-   * Handles a change to the viewport.
-   */
-  viewportChanged() {}
-
-  /**
-   * Rotates the document 90 degrees in the clockwise direction.
-   * @abstract
-   */
-  rotateClockwise() {}
-
-  /**
-   * Rotates the document 90 degrees in the counter clockwise direction.
-   * @abstract
-   */
-  rotateCounterclockwise() {}
-
-  /**
-   * Triggers printing of the current document.
-   */
-  print() {}
-
-  /**
-   * Undo an edit action.
-   */
-  undo() {}
-
-  /**
-   * Redo an edit action.
-   */
-  redo() {}
-
-  /**
-   * Requests that the current document be saved.
-   * @param {boolean} requireResult whether a response is required, otherwise
-   *     the controller may save the document to disk internally.
-   * @return {Promise<{fileName: string, dataToSave: ArrayBuffer}}
-   * @abstract
-   */
-  save(requireResult) {}
-
-  /**
-   * Loads PDF document from `data` activates UI.
-   * @param {string} fileName
-   * @param {ArrayBuffer} data
-   * @return {Promise<void>}
-   * @abstract
-   */
-  load(fileName, data) {}
-
-  /**
-   * Unloads the current document and removes the UI.
-   * @abstract
-   */
-  unload() {}
-}
-
-class InkController extends ContentController {
-  /**
-   * @param {PDFViewer} viewer
-   * @param {Viewport} viewport
-   */
-  constructor(viewer, viewport) {
-    super();
-    this.viewer_ = viewer;
-    this.viewport_ = viewport;
-
-    /** @type {ViewerInkHost} */
-    this.inkHost_ = null;
   }
 
-  /** @param {AnnotationTool} tool */
-  setAnnotationTool(tool) {
-    this.tool_ = tool;
-    if (this.inkHost_) {
-      this.inkHost_.setAnnotationTool(tool);
-    }
-  }
-
-  /** @override */
-  rotateClockwise() {
-    // TODO(dstockwell): implement rotation
-  }
-
-  /** @override */
-  rotateCounterclockwise() {
-    // TODO(dstockwell): implement rotation
-  }
-
-  /** @override */
-  viewportChanged() {
-    this.inkHost_.viewportChanged();
-  }
-
-  /** @override */
-  save(requireResult) {
-    return this.inkHost_.saveDocument();
-  }
-
-  /** @override */
-  undo() {
-    this.inkHost_.undo();
-  }
-
-  /** @override */
-  redo() {
-    this.inkHost_.redo();
-  }
-
-  /** @override */
-  load(filename, data) {
-    if (!this.inkHost_) {
-      this.inkHost_ = document.createElement('viewer-ink-host');
-      $('content').appendChild(this.inkHost_);
-      this.inkHost_.viewport = this.viewport_;
-      this.inkHost_.addEventListener('stroke-added', e => {
-        this.viewer_.setHasUnsavedChanges();
-      });
-      this.inkHost_.addEventListener('undo-state-changed', e => {
-        this.viewer_.setAnnotationUndoState(e.detail);
-      });
-    }
-    return this.inkHost_.load(filename, data);
-  }
-
-  /** @override */
-  unload() {
-    this.inkHost_.remove();
-    this.inkHost_ = null;
-  }
-}
-
-class PluginController extends ContentController {
   /**
-   * @param {HTMLEmbedElement} plugin
-   * @param {PDFViewer} viewer
-   * @param {Viewport} viewport
-   */
-  constructor(plugin, viewer, viewport) {
-    super();
-    this.plugin_ = plugin;
-    this.viewer_ = viewer;
-    this.viewport_ = viewport;
-
-    /** @private {!Map<string, PromiseResolver>} */
-    this.pendingTokens_ = new Map();
-    this.plugin_.addEventListener(
-        'message', e => this.handlePluginMessage_(e), false);
-  }
-
-  /**
-   * Notify the plugin to stop reacting to scroll events while zoom is taking
-   * place to avoid flickering.
-   * @override
-   */
-  beforeZoom() {
-    this.postMessage({type: 'stopScrolling'});
-
-    if (this.viewport_.pinchPhase == Viewport.PinchPhase.PINCH_START) {
-      const position = this.viewport_.position;
-      const zoom = this.viewport_.getZoom();
-      const pinchPhase = this.viewport_.pinchPhase;
-      this.postMessage({
-        type: 'viewport',
-        userInitiated: true,
-        zoom: zoom,
-        xOffset: position.x,
-        yOffset: position.y,
-        pinchPhase: pinchPhase
-      });
-    }
-  }
-
-  /**
-   * Notify the plugin of the zoom change and to continue reacting to scroll
-   * events.
-   * @override
-   */
-  afterZoom() {
-    const position = this.viewport_.position;
-    const zoom = this.viewport_.getZoom();
-    const pinchVector = this.viewport_.pinchPanVector || {x: 0, y: 0};
-    const pinchCenter = this.viewport_.pinchCenter || {x: 0, y: 0};
-    const pinchPhase = this.viewport_.pinchPhase;
-
-    this.postMessage({
-      type: 'viewport',
-      userInitiated: this.viewer_.isUserInitiatedEvent_,
-      zoom: zoom,
-      xOffset: position.x,
-      yOffset: position.y,
-      pinchPhase: pinchPhase,
-      pinchX: pinchCenter.x,
-      pinchY: pinchCenter.y,
-      pinchVectorX: pinchVector.x,
-      pinchVectorY: pinchVector.y
-    });
-  }
-
-  // TODO(dstockwell): this method should be private, add controller APIs that
-  // map to all of the existing usage. crbug.com/913279
-  /**
-   * Post a message to the PPAPI plugin. Some messages will cause an async reply
-   * to be received through handlePluginMessage_().
-   *
-   * @param {Object} message Message to post.
+   * @param {!CustomEvent<{canUndo: boolean, canRedo: boolean}>} e
+   * @private
    */
-  postMessage(message) {
-    this.plugin_.postMessage(message);
-  }
-
-  /** @override */
-  rotateClockwise() {
-    this.postMessage({type: 'rotateClockwise'});
-  }
-
-  /** @override */
-  rotateCounterclockwise() {
-    this.postMessage({type: 'rotateCounterclockwise'});
-  }
-
-  /** @override */
-  print() {
-    this.postMessage({type: 'print'});
-  }
-
-  /** @override */
-  save(requireResult) {
-    const resolver = new PromiseResolver();
-    const newToken = createToken();
-    this.pendingTokens_.set(newToken, resolver);
-    this.postMessage({type: 'save', token: newToken, force: requireResult});
-    return resolver.promise;
+  setAnnotationUndoState_(e) {
+    this.toolbar_.canUndoAnnotation = e.detail.canUndo;
+    this.toolbar_.canRedoAnnotation = e.detail.canRedo;
   }
 
-  /** @override */
-  async load(fileName, data) {
-    const url = URL.createObjectURL(new Blob([data]));
-    this.plugin_.removeAttribute('headers');
-    this.plugin_.setAttribute('stream-url', url);
-    this.plugin_.style.display = 'block';
-    try {
-      await this.viewer_.loaded;
-    } finally {
-      URL.revokeObjectURL(url);
-    }
-  }
-
-  /** @override */
-  unload() {
-    this.plugin_.style.display = 'none';
-  }
-
-  /**
-   * An event handler for handling message events received from the plugin.
-   *
-   * @param {MessageObject} message a message event.
-   * @private
-   */
-  handlePluginMessage_(message) {
-    switch (message.data.type.toString()) {
-      case 'beep':
-        this.viewer_.handleBeep();
-        break;
-      case 'documentDimensions':
-        this.viewer_.setDocumentDimensions(message.data);
-        break;
-      case 'email':
-        const href = 'mailto:' + message.data.to + '?cc=' + message.data.cc +
-            '&bcc=' + message.data.bcc + '&subject=' + message.data.subject +
-            '&body=' + message.data.body;
-        window.location.href = href;
-        break;
-      case 'getPassword':
-        this.viewer_.handlePasswordRequest();
-        break;
-      case 'getSelectedTextReply':
-        this.viewer_.handleSelectedTextReply(message.data.selectedText);
-        break;
-      case 'goToPage':
-        this.viewport_.goToPage(message.data.page);
-        break;
-      case 'loadProgress':
-        this.viewer_.updateProgress(message.data.progress);
-        break;
-      case 'navigate':
-        this.viewer_.handleNavigate(message.data.url, message.data.disposition);
-        break;
-      case 'printPreviewLoaded':
-        this.viewer_.handlePrintPreviewLoaded();
-        break;
-      case 'setScrollPosition':
-        this.viewport_.scrollTo(/** @type {!PartialPoint} */ (message.data));
-        break;
-      case 'scrollBy':
-        this.viewport_.scrollBy(/** @type {!Point} */ (message.data));
-        break;
-      case 'metadata':
-        this.viewer_.setDocumentMetadata(
-            message.data.title, message.data.bookmarks,
-            message.data.canSerializeDocument);
-        break;
-      case 'setIsSelecting':
-        this.viewer_.setIsSelecting(message.data.isSelecting);
-        break;
-      case 'getNamedDestinationReply':
-        this.viewer_.paramsParser_.onNamedDestinationReceived(
-            message.data.pageNumber);
-        break;
-      case 'formFocusChange':
-        this.viewer_.setIsFormFieldFocused(message.data.focused);
-        break;
-      case 'saveData':
-        this.saveData_(message.data);
-        break;
-      case 'consumeSaveToken':
-        const resolver = this.pendingTokens_.get(message.data.token);
-        assert(this.pendingTokens_.delete(message.data.token));
-        resolver.resolve(null);
-        break;
+  /** @private */
+  resetTrackers_() {
+    this.viewport_.resetTracker();
+    if (this.tracker_) {
+      this.tracker_.removeAll();
     }
   }
+}
 
-  /**
-   * Handles the pdf file buffer received from the plugin.
-   *
-   * @param {SaveDataMessageData} messageData data of the message event.
-   * @private
-   */
-  saveData_(messageData) {
-    assert(
-        loadTimeData.getBoolean('pdfFormSaveEnabled') ||
-        loadTimeData.getBoolean('pdfAnnotationsEnabled'));
-
-    // Verify a token that was created by this instance is included to avoid
-    // being spammed.
-    const resolver = this.pendingTokens_.get(messageData.token);
-    assert(this.pendingTokens_.delete(messageData.token));
+/**
+ * The height of the toolbar along the top of the page. The document will be
+ * shifted down by this much in the viewport.
+ */
+PDFViewer.MATERIAL_TOOLBAR_HEIGHT = 56;
 
-    if (!messageData.dataToSave) {
-      resolver.reject();
-      return;
-    }
+/**
+ * Minimum height for the material toolbar to show (px). Should match the media
+ * query in index-material.css. If the window is smaller than this at load,
+ * leave no space for the toolbar.
+ */
+PDFViewer.TOOLBAR_WINDOW_MIN_HEIGHT = 250;
 
-    // Verify the file size and the first bytes to make sure it's a PDF. Cap at
-    // 100 MB. This cap should be kept in sync with and is also enforced in
-    // pdf/out_of_process_instance.cc.
-    const MIN_FILE_SIZE = '%PDF1.0'.length;
-    const MAX_FILE_SIZE = 100 * 1000 * 1000;
+/**
+ * The background color used for print preview (--google-grey-refresh-300).
+ */
+PDFViewer.PRINT_PREVIEW_BACKGROUND_COLOR = '0xFFDADCE0';
 
-    const buffer = messageData.dataToSave;
-    const bufView = new Uint8Array(buffer);
-    assert(
-        bufView.length <= MAX_FILE_SIZE,
-        `File too large to be saved: ${bufView.length} bytes.`);
-    assert(bufView.length >= MIN_FILE_SIZE);
-    assert(
-        String.fromCharCode(bufView[0], bufView[1], bufView[2], bufView[3]) ==
-        '%PDF');
+/**
+ * The background color used for print preview when dark mode is enabled
+ * (--google-grey-refresh-700).
+ */
+PDFViewer.PRINT_PREVIEW_DARK_BACKGROUND_COLOR = '0xFF5F6368';
 
-    resolver.resolve(messageData);
-  }
-}
+/**
+ * The background color used for the regular viewer.
+ */
+PDFViewer.BACKGROUND_COLOR = '0xFF525659';
diff --git a/chromium/chrome/browser/resources/pdf/toolbar_manager.js b/chromium/chrome/browser/resources/pdf/toolbar_manager.js
index 255bc3394f1..8a2b06c135c 100644
--- a/chromium/chrome/browser/resources/pdf/toolbar_manager.js
+++ b/chromium/chrome/browser/resources/pdf/toolbar_manager.js
@@ -20,10 +20,8 @@ const TOP_TOOLBAR_REVEAL_DISTANCE = 100;
 const SIDE_TOOLBAR_REVEAL_DISTANCE_RIGHT = 150;
 const SIDE_TOOLBAR_REVEAL_DISTANCE_BOTTOM = 250;
 
-
-
 /**
- * @param {MouseEvent} e Event to test.
+ * @param {!MouseEvent} e Event to test.
  * @return {boolean} True if the mouse is close to the top of the screen.
  */
 function isMouseNearTopToolbar(e) {
@@ -31,7 +29,7 @@ function isMouseNearTopToolbar(e) {
 }
 
 /**
- * @param {MouseEvent} e Event to test.
+ * @param {!MouseEvent} e Event to test.
  * @param {Window} window Window to test against.
  * @param {boolean} reverse Whether the side toolbar is reversed.
  * @return {boolean} True if the mouse is close to the bottom-right of the
@@ -47,47 +45,60 @@ function isMouseNearSideToolbar(e, window, reverse) {
   return atSide && atBottom;
 }
 
-/**
- * Constructs a Toolbar Manager, responsible for co-ordinating between multiple
- * toolbar elements.
- *
- * @param {Object} window The window containing the UI.
- * @param {Object} toolbar The top toolbar element.
- * @param {Object} zoomToolbar The zoom toolbar element.
- * @constructor
- */
-function ToolbarManager(window, toolbar, zoomToolbar) {
-  this.window_ = window;
-  this.toolbar_ = toolbar;
-  this.zoomToolbar_ = zoomToolbar;
+/** Responsible for co-ordinating between multiple toolbar elements. */
+class ToolbarManager {
+  /**
+   * @param {!Window} window The window containing the UI.
+   * @param {?ViewerPdfToolbarElement} toolbar
+   * @param {!ViewerZoomToolbarElement} zoomToolbar
+   */
+  constructor(window, toolbar, zoomToolbar) {
+    /** @private {!Window} */
+    this.window_ = window;
 
-  this.toolbarTimeout_ = null;
-  this.isMouseNearTopToolbar_ = false;
-  this.isMouseNearSideToolbar_ = false;
+    /** @private {?ViewerPdfToolbarElement} */
+    this.toolbar_ = toolbar;
 
-  this.sideToolbarAllowedOnly_ = false;
-  this.sideToolbarAllowedOnlyTimer_ = null;
+    /** @private {!ViewerZoomToolbarElement} */
+    this.zoomToolbar_ = zoomToolbar;
 
-  this.keyboardNavigationActive = false;
+    /** @private {?number} */
+    this.toolbarTimeout_ = null;
 
-  this.lastMovementTimestamp = null;
+    /** @private {boolean} */
+    this.isMouseNearTopToolbar_ = false;
 
-  this.reverseSideToolbar_ = false;
+    /** @private {boolean} */
+    this.isMouseNearSideToolbar_ = false;
 
-  this.window_.addEventListener('resize', this.resizeDropdowns_.bind(this));
-  this.resizeDropdowns_();
+    /** @private {boolean} */
+    this.sideToolbarAllowedOnly_ = false;
 
-  if (zoomToolbar.isPrintPreview()) {
-    this.zoomToolbar_.addEventListener('keyboard-navigation-active', e => {
-      this.keyboardNavigationActive = e.detail;
-    });
-  }
-}
+    /** @private {?number} */
+    this.sideToolbarAllowedOnlyTimer_ = null;
+
+    /** @private {boolean} */
+    this.keyboardNavigationActive = false;
+
+    /** @private {?number} */
+    this.lastMovementTimestamp = null;
 
-ToolbarManager.prototype = {
+    /** @private {boolean} */
+    this.reverseSideToolbar_ = false;
+
+    this.window_.addEventListener('resize', this.resizeDropdowns_.bind(this));
+    this.resizeDropdowns_();
+
+    if (zoomToolbar.isPrintPreview()) {
+      this.zoomToolbar_.addEventListener('keyboard-navigation-active', e => {
+        this.keyboardNavigationActive = e.detail;
+      });
+    }
+  }
 
-  handleMouseMove: function(e) {
-    this.isMouseNearTopToolbar_ = this.toolbar_ && isMouseNearTopToolbar(e);
+  /** @param {!MouseEvent} e */
+  handleMouseMove(e) {
+    this.isMouseNearTopToolbar_ = !!this.toolbar_ && isMouseNearTopToolbar(e);
     this.isMouseNearSideToolbar_ =
         isMouseNearSideToolbar(e, this.window_, this.reverseSideToolbar_);
 
@@ -123,17 +134,16 @@ ToolbarManager.prototype = {
       }
     }
     this.hideToolbarsAfterTimeout();
-  },
+  }
 
   /**
    * Whether a mousemove event is high enough velocity to reveal the toolbars.
-   *
-   * @param {MouseEvent} e Event to test.
+   * @param {!MouseEvent} e Event to test.
    * @return {boolean} true if the event is a high velocity mousemove, false
    * otherwise.
    * @private
    */
-  isHighVelocityMouseMove_: function(e) {
+  isHighVelocityMouseMove_(e) {
     if (e.type == 'mousemove') {
       if (this.lastMovementTimestamp == null) {
         this.lastMovementTimestamp = this.getCurrentTimestamp_();
@@ -150,54 +160,51 @@ ToolbarManager.prototype = {
       }
     }
     return false;
-  },
+  }
 
   /**
    * Wrapper around Date.now() to make it easily replaceable for testing.
-   *
    * @return {number}
    * @private
    */
-  getCurrentTimestamp_: function() {
+  getCurrentTimestamp_() {
     return Date.now();
-  },
+  }
 
-  /**
-   * Display both UI toolbars.
-   */
-  showToolbars: function() {
+  /** Display both UI toolbars. */
+  showToolbars() {
     if (this.toolbar_) {
       this.toolbar_.show();
     }
     this.zoomToolbar_.show();
-  },
+  }
 
   /**
    * Show toolbars and mark that navigation is being performed with
    * tab/shift-tab. This disables toolbar hiding until the mouse is moved or
    * escape is pressed.
    */
-  showToolbarsForKeyboardNavigation: function() {
+  showToolbarsForKeyboardNavigation() {
     this.keyboardNavigationActive = true;
     this.showToolbars();
-  },
+  }
 
   /**
    * Hide toolbars after a delay, regardless of the position of the mouse.
    * Intended to be called when the mouse has moved out of the parent window.
    */
-  hideToolbarsForMouseOut: function() {
+  hideToolbarsForMouseOut() {
     this.isMouseNearTopToolbar_ = false;
     this.isMouseNearSideToolbar_ = false;
     this.hideToolbarsAfterTimeout();
-  },
+  }
 
   /**
    * Check if the toolbars are able to be closed, and close them if they are.
    * Toolbars may be kept open based on mouse/keyboard activity and active
    * elements.
    */
-  hideToolbarsIfAllowed: function() {
+  hideToolbarsIfAllowed() {
     if (this.isMouseNearSideToolbar_ || this.isMouseNearTopToolbar_) {
       return;
     }
@@ -221,47 +228,44 @@ ToolbarManager.prototype = {
       this.toolbar_.hide();
     }
     this.zoomToolbar_.hide();
-  },
+  }
 
-  /**
-   * Hide the toolbar after the HIDE_TIMEOUT has elapsed.
-   */
-  hideToolbarsAfterTimeout: function() {
+  /** Hide the toolbars after the HIDE_TIMEOUT has elapsed. */
+  hideToolbarsAfterTimeout() {
     if (this.toolbarTimeout_) {
       this.window_.clearTimeout(this.toolbarTimeout_);
     }
     this.toolbarTimeout_ = this.window_.setTimeout(
         this.hideToolbarsIfAllowed.bind(this), HIDE_TIMEOUT);
-  },
+  }
 
   /**
    * Hide the 'topmost' layer of toolbars. Hides any dropdowns that are open, or
    * hides the basic toolbars otherwise.
    */
-  hideSingleToolbarLayer: function() {
+  hideSingleToolbarLayer() {
     if (!this.toolbar_ || !this.toolbar_.hideDropdowns()) {
       this.keyboardNavigationActive = false;
       this.hideToolbarsIfAllowed();
     }
-  },
+  }
 
   /**
    * Clears the keyboard navigation state and hides the toolbars after a delay.
    */
-  resetKeyboardNavigationAndHideToolbars: function() {
+  resetKeyboardNavigationAndHideToolbars() {
     this.keyboardNavigationActive = false;
     this.hideToolbarsAfterTimeout();
-  },
+  }
 
   /**
    * Hide the top toolbar and keep it hidden until both:
    * - The mouse is moved away from the right side of the screen
    * - 1 second has passed.
-   *
    * The top toolbar can be immediately re-opened by moving the mouse to the top
    * of the screen.
    */
-  forceHideTopToolbar: function() {
+  forceHideTopToolbar() {
     if (!this.toolbar_) {
       return;
     }
@@ -270,20 +274,19 @@ ToolbarManager.prototype = {
     this.sideToolbarAllowedOnlyTimer_ = this.window_.setTimeout(() => {
       this.sideToolbarAllowedOnlyTimer_ = null;
     }, FORCE_HIDE_TIMEOUT);
-  },
+  }
 
   /** Reverse the position of the side toolbar. */
-  reverseSideToolbar: function() {
+  reverseSideToolbar() {
     this.reverseSideToolbar_ = true;
-  },
+  }
 
   /**
    * Updates the size of toolbar dropdowns based on the positions of the rest of
    * the UI.
-   *
    * @private
    */
-  resizeDropdowns_: function() {
+  resizeDropdowns_() {
     if (!this.toolbar_) {
       return;
     }
@@ -291,4 +294,4 @@ ToolbarManager.prototype = {
         this.window_.innerHeight - this.zoomToolbar_.clientHeight;
     this.toolbar_.setDropdownLowerBound(lowerBound);
   }
-};
+}
diff --git a/chromium/chrome/browser/resources/pdf/viewport.js b/chromium/chrome/browser/resources/pdf/viewport.js
index 480664c014c..17986ae5d81 100644
--- a/chromium/chrome/browser/resources/pdf/viewport.js
+++ b/chromium/chrome/browser/resources/pdf/viewport.js
@@ -6,14 +6,21 @@
  * @typedef {{
  *   width: number,
  *   height: number,
+ *   layoutOptions: (!LayoutOptions|undefined),
  *   pageDimensions: Array<ViewportRect>,
  * }}
  */
 let DocumentDimensions;
 
+/** @typedef {{defaultPageOrientation: number}} */
+let LayoutOptions;
+
 /** @typedef {{x: number, y: number}} */
 let Point;
 
+/** @typedef {{x: (number|undefined), y: (number|undefined)}} */
+let PartialPoint;
+
 /** @typedef {{width: number, height: number}} */
 let Size;
 
@@ -279,6 +286,15 @@ class Viewport {
   }
 
   /**
+   * @return {!LayoutOptions|undefined} A dictionary carrying layout options
+   *     from the plugin.
+   */
+  getLayoutOptions() {
+    return this.documentDimensions_ ? this.documentDimensions_.layoutOptions :
+                                      undefined;
+  }
+
+  /**
    * @return {!ViewportRect} ViewportRect for the viewport given current zoom.
    * @private
    */
@@ -605,7 +621,7 @@ class Viewport {
       const bottom =
           this.pageDimensions_[page].y + this.pageDimensions_[page].height;
 
-      if (top <= y && bottom > y) {
+      if (top <= y && y <= bottom) {
         return page;
       }
 
@@ -1166,7 +1182,9 @@ class Viewport {
         this.fittingType_ == FittingType.FIT_TO_HEIGHT);
   }
 
-  /** @param {!Point} point The position to which to scroll the viewport. */
+  /**
+   * @param {!PartialPoint} point The position to which to scroll the viewport.
+   */
   scrollTo(point) {
     let changed = false;
     const newPosition = this.position;
diff --git a/chromium/chrome/browser/resources/pdf/viewport_scroller.js b/chromium/chrome/browser/resources/pdf/viewport_scroller.js
index bb8c187d478..ca16c9cf7d2 100644
--- a/chromium/chrome/browser/resources/pdf/viewport_scroller.js
+++ b/chromium/chrome/browser/resources/pdf/viewport_scroller.js
@@ -5,75 +5,61 @@
 'use strict';
 
 /**
- * The period of time in milliseconds to wait between updating the viewport
- * position by the scroll velocity.
- *
- * @private
- */
-ViewportScroller.DRAG_TIMER_INTERVAL_MS_ = 100;
-
-/**
- * The maximum drag scroll distance per DRAG_TIMER_INTERVAL in pixels.
- *
- * @private
- */
-ViewportScroller.MAX_DRAG_SCROLL_DISTANCE_ = 100;
-
-/**
  * Creates a new ViewportScroller.
  * A ViewportScroller scrolls the page in response to drag selection with the
  * mouse.
  *
- * @param {Object} viewport The viewport info of the page.
- * @param {Object} plugin The PDF plugin element.
- * @param {Object} window The window containing the viewer.
- * @constructor
  */
-function ViewportScroller(viewport, plugin, window) {
-  this.viewport_ = viewport;
-  this.plugin_ = plugin;
-  this.window_ = window;
-  this.mousemoveCallback_ = null;
-  this.timerId_ = null;
-  this.scrollVelocity_ = null;
-  this.lastFrameTime_ = 0;
-}
+class ViewportScroller {
+  /**
+   * @param {Object} viewport The viewport info of the page.
+   * @param {Object} plugin The PDF plugin element.
+   * @param {Object} window The window containing the viewer.
+   */
+  constructor(viewport, plugin, window) {
+    this.viewport_ = viewport;
+    this.plugin_ = plugin;
+    this.window_ = window;
+    this.mousemoveCallback_ = null;
+    this.timerId_ = null;
+    this.scrollVelocity_ = null;
+    this.lastFrameTime_ = 0;
+  }
 
-ViewportScroller.prototype = {
   /**
    * Start scrolling the page by |scrollVelocity_| every
    * |DRAG_TIMER_INTERVAL_MS_|.
    *
    * @private
    */
-  startDragScrollTimer_: function() {
+  startDragScrollTimer_() {
     if (this.timerId_ === null) {
       this.timerId_ = this.window_.setInterval(
           this.dragScrollPage_.bind(this),
           ViewportScroller.DRAG_TIMER_INTERVAL_MS_);
       this.lastFrameTime_ = Date.now();
     }
-  },
+  }
 
   /**
    * Stops the drag scroll timer if it is active.
    *
    * @private
    */
-  stopDragScrollTimer_: function() {
+  stopDragScrollTimer_() {
     if (this.timerId_ !== null) {
       this.window_.clearInterval(this.timerId_);
       this.timerId_ = null;
       this.lastFrameTime_ = 0;
     }
-  },
+  }
 
   /**
    * Scrolls the viewport by the current scroll velocity.
    *
    * @private
    */
-  dragScrollPage_: function() {
+  dragScrollPage_() {
     const position = this.viewport_.position;
     const currentFrameTime = Date.now();
     const timeAdjustment = (currentFrameTime - this.lastFrameTime_) /
@@ -82,7 +68,7 @@ ViewportScroller.prototype = {
     position.x += (this.scrollVelocity_.x * timeAdjustment);
     this.viewport_.position = position;
     this.lastFrameTime_ = currentFrameTime;
-  },
+  }
 
   /**
    * Calculate the velocity to scroll while dragging using the distance of the
@@ -92,7 +78,7 @@ ViewportScroller.prototype = {
    * @return {Object} Object with x and y direction scroll velocity.
    * @private
    */
-  calculateVelocity_: function(event) {
+  calculateVelocity_(event) {
     const x =
         Math.min(
             Math.max(
@@ -106,7 +92,7 @@ ViewportScroller.prototype = {
             ViewportScroller.MAX_DRAG_SCROLL_DISTANCE_) *
         Math.sign(event.offsetY);
     return {x: x, y: y};
-  },
+  }
 
   /**
    * Handles mousemove events. It updates the scroll velocity and starts and
@@ -115,14 +101,14 @@ ViewportScroller.prototype = {
    * @param {Object} event The mousemove event.
    * @private
    */
-  onMousemove_: function(event) {
+  onMousemove_(event) {
     this.scrollVelocity_ = this.calculateVelocity_(event);
     if (!this.scrollVelocity_.x && !this.scrollVelocity_.y) {
       this.stopDragScrollTimer_();
     } else if (!this.timerId_) {
       this.startDragScrollTimer_();
     }
-  },
+  }
 
   /**
    * Sets whether to scroll the viewport when the mouse is outside the
@@ -130,7 +116,7 @@ ViewportScroller.prototype = {
    *
    * @param {boolean} isSelecting Represents selection status.
    */
-  setEnableScrolling: function(isSelecting) {
+  setEnableScrolling(isSelecting) {
     if (isSelecting) {
       if (!this.mousemoveCallback_) {
         this.mousemoveCallback_ = this.onMousemove_.bind(this);
@@ -145,4 +131,19 @@ ViewportScroller.prototype = {
       }
     }
   }
-};
+}
+
+/**
+ * The period of time in milliseconds to wait between updating the viewport
+ * position by the scroll velocity.
+ *
+ * @private
+ */
+ViewportScroller.DRAG_TIMER_INTERVAL_MS_ = 100;
+
+/**
+ * The maximum drag scroll distance per DRAG_TIMER_INTERVAL in pixels.
+ *
+ * @private
+ */
+ViewportScroller.MAX_DRAG_SCROLL_DISTANCE_ = 100;