BASELINE: Update Chromium to 65.0.3525.40

Also imports missing submodules

Change-Id: I36901b7c6a325cda3d2c10cedb2186c25af3b79b
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

12 files changed, 369 insertions, 27 deletions

diff --git a/chromium/chrome/browser/resources/pdf/compiled_resources2.gyp b/chromium/chrome/browser/resources/pdf/compiled_resources2.gyp
index 655323d32f2..eae4c571a9e 100644
--- a/chromium/chrome/browser/resources/pdf/compiled_resources2.gyp
+++ b/chromium/chrome/browser/resources/pdf/compiled_resources2.gyp
@@ -18,6 +18,10 @@
       'includes': ['../../../../third_party/closure_compiler/compile_js2.gypi'],
     },
     {
+      'target_name': 'coords_transformer',
+      'includes': ['../../../../third_party/closure_compiler/compile_js2.gypi'],
+    },
+    {
       'target_name': 'gesture_detector',
       'includes': ['../../../../third_party/closure_compiler/compile_js2.gypi'],
     },
diff --git a/chromium/chrome/browser/resources/pdf/coords_transformer.js b/chromium/chrome/browser/resources/pdf/coords_transformer.js
new file mode 100644
index 00000000000..43a073f736d
--- /dev/null
+++ b/chromium/chrome/browser/resources/pdf/coords_transformer.js
@@ -0,0 +1,72 @@
+// 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.
+
+/**
+ * @typedef {{
+ *   callback: function(Object, Object):void,
+ *   params: Object
+ * }}
+ */
+let TransformPagePointRequest;
+
+/**
+ * @typedef {{
+ *   type: string,
+ *   id: number,
+ *   page: number,
+ *   x: number,
+ *   y: number
+ * }}
+ */
+let TransformPagePointMessage;
+
+(function() {
+
+'use strict';
+
+/**
+ * Transforms page to screen coordinates using messages to the plugin.
+ */
+window.PDFCoordsTransformer = class {
+  constructor(postMessageCallback) {
+    /** @private {!Map<number,!TransformPagePointRequest>} */
+    this.outstandingTransformPagePointRequests_ = new Map();
+
+    /** @private {function(TransformPagePointMessage):void} */
+    this.postMessageCallback_ = postMessageCallback;
+
+    /** @private {number} */
+    this.nextId_ = 0;
+  }
+
+  /**
+   * Send a 'transformPagePoint' message to the plugin.
+   * @param {function(Object, Object):void} callback Function to call when the
+   *     response is received.
+   * @param {Object} params User parameters to be used in |callback|.
+   * @param {number} page 0-based page number of the page where the point is.
+   * @param {number} x x coordinate of the point.
+   * @param {number} y y coordinate of the point.
+   */
+  request(callback, params, page, x, y) {
+    this.outstandingTransformPagePointRequests_.set(
+        this.nextId_, {callback: callback, params: params});
+    this.postMessageCallback_(
+        {type: 'transformPagePoint', id: this.nextId_, page: page, x: x, y: y});
+    this.nextId_++;
+  }
+
+  /**
+   * Call when 'transformPagePointReply' is received from the plugin.
+   * @param {Object} message The message received from the plugin.
+   */
+  onReplyReceived(message) {
+    const outstandingRequest =
+        this.outstandingTransformPagePointRequests_.get(message.data.id);
+    this.outstandingTransformPagePointRequests_.delete(message.data.id);
+    outstandingRequest.callback(message.data, outstandingRequest.params);
+  }
+};
+
+}());
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js
index de21ff24b32..a78e9d2f383 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-bookmark/viewer-bookmark.js
@@ -66,11 +66,15 @@ Polymer({
   onClick: function() {
     if (this.bookmark.hasOwnProperty('page')) {
       if (this.bookmark.hasOwnProperty('y')) {
-        this.fire(
-            'change-page-and-y',
-            {page: this.bookmark.page, y: this.bookmark.y});
+        this.fire('change-page-and-xy', {
+          page: this.bookmark.page,
+          x: 0,
+          y: this.bookmark.y,
+          origin: 'bookmark'
+        });
       } else {
-        this.fire('change-page', {page: this.bookmark.page});
+        this.fire(
+            'change-page', {page: this.bookmark.page, origin: 'bookmark'});
       }
     } else if (this.bookmark.hasOwnProperty('uri')) {
       this.fire('navigate', {uri: this.bookmark.uri, newtab: true});
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/viewer-page-selector.js
index 198b551805a..a0b018805e1 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/viewer-page-selector.js
@@ -25,7 +25,7 @@ Polymer({
     var page = parseInt(this.$.input.value, 10);
 
     if (!isNaN(page) && page <= this.docLength && page > 0)
-      this.fire('change-page', {page: page - 1});
+      this.fire('change-page', {page: page - 1, origin: 'pageselector'});
     else
       this.$.input.value = this.pageNo;
     this.$.input.blur();
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/viewer-pdf-toolbar.html
index 1a99c68e78a..1d5c1ad9bb5 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/viewer-pdf-toolbar.html
@@ -147,6 +147,7 @@
           </paper-icon-button>
 
           <viewer-toolbar-dropdown id="bookmarks"
+                                   metrics-id="bookmarks"
                                    hidden$="[[!bookmarks.length]]"
                                    open-icon="pdf:bookmark"
                                    closed-icon="pdf:bookmark-border"
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/viewer-toolbar-dropdown.js
index f1751dd3306..33987f3eb94 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/viewer-toolbar-dropdown.js
@@ -27,6 +27,9 @@ Polymer({
     /** Icon to display when the dropdown is open. */
     openIcon: String,
 
+    /** Unique id to identify this dropdown for metrics purposes. */
+    metricsId: String,
+
     /** True if the dropdown is currently open. */
     dropdownOpen: {type: Boolean, reflectToAttribute: true, value: false},
 
@@ -66,6 +69,7 @@ Polymer({
       this.$.dropdown.style.display = 'block';
       if (!this.maxHeightValid_)
         this.updateMaxHeight();
+      this.fire('dropdown-opened', this.metricsId);
     }
     this.cancelAnimation_();
     this.playAnimation_(this.dropdownOpen);
diff --git a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js
index 565cc488334..2854e8b8f40 100644
--- a/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js
+++ b/chromium/chrome/browser/resources/pdf/elements/viewer-zoom-toolbar/viewer-zoom-toolbar.js
@@ -38,7 +38,8 @@ Polymer({
     this.fireFitToChangedEvent_(
         this.$['fit-button'].activeIndex == FIT_TO_WIDTH_BUTTON_STATE ?
             FittingType.FIT_TO_WIDTH :
-            FittingType.FIT_TO_PAGE);
+            FittingType.FIT_TO_PAGE,
+        true);
   },
 
   /**
@@ -60,7 +61,7 @@ Polymer({
    * @param {FittingType} fittingType Page fitting type to force.
    */
   forceFit: function(fittingType) {
-    this.fireFitToChangedEvent_(fittingType);
+    this.fireFitToChangedEvent_(fittingType, false);
 
     // Set the button state since there was no mouse click.
     var nextButtonState =
@@ -73,9 +74,13 @@ Polymer({
    * @private
    * Fire a 'fit-to-changed' {CustomEvent} with the given FittingType as detail.
    * @param {FittingType} fittingType to include as payload.
+   * @param {boolean} userInitiated whether the event was initiated by a user
+   *     action.
    */
-  fireFitToChangedEvent_: function(fittingType) {
-    this.fire('fit-to-changed', fittingType);
+  fireFitToChangedEvent_: function(fittingType, userInitiated) {
+    this.fire(
+        'fit-to-changed',
+        {fittingType: fittingType, userInitiated: userInitiated});
   },
 
   /**
diff --git a/chromium/chrome/browser/resources/pdf/index.html b/chromium/chrome/browser/resources/pdf/index.html
index 96a13be132e..69c1c39c8c4 100644
--- a/chromium/chrome/browser/resources/pdf/index.html
+++ b/chromium/chrome/browser/resources/pdf/index.html
@@ -39,6 +39,8 @@
 <script src="pdf_scripting_api.js"></script>
 <script src="chrome://resources/js/util.js"></script>
 <script src="browser_api.js"></script>
+<script src="coords_transformer.js"></script>
+<script src="metrics.js"></script>
 <script src="pdf.js"></script>
 <script src="main.js"></script>
 </html>
diff --git a/chromium/chrome/browser/resources/pdf/manifest.json b/chromium/chrome/browser/resources/pdf/manifest.json
index 33a1e96fc7a..3b45a058c94 100644
--- a/chromium/chrome/browser/resources/pdf/manifest.json
+++ b/chromium/chrome/browser/resources/pdf/manifest.json
@@ -9,6 +9,7 @@
   "incognito": "split",
   "permissions": [
     "<all_urls>",
+    "metricsPrivate",
     "resourcesPrivate"
   ],
   "mime_types": [
diff --git a/chromium/chrome/browser/resources/pdf/metrics.js b/chromium/chrome/browser/resources/pdf/metrics.js
new file mode 100644
index 00000000000..61091cd4dc1
--- /dev/null
+++ b/chromium/chrome/browser/resources/pdf/metrics.js
@@ -0,0 +1,206 @@
+// Copyright 2017 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() {
+
+'use strict';
+
+// Keep in sync with enums.xml.
+// Do not change the numeric values or reuse them since these numbers are
+// persisted to logs.
+const UserAction = {
+  DOCUMENT_OPENED: 0,  // Baseline to use as denominator for all formulas.
+  ROTATE_FIRST: 1,
+  ROTATE: 2,
+  FIT_TO_WIDTH_FIRST: 3,
+  FIT_TO_WIDTH: 4,
+  FIT_TO_PAGE_FIRST: 5,
+  FIT_TO_PAGE: 6,
+  OPEN_BOOKMARKS_PANEL_FIRST: 7,
+  OPEN_BOOKMARKS_PANEL: 8,
+  FOLLOW_BOOKMARK_FIRST: 9,
+  FOLLOW_BOOKMARK: 10,
+  PAGE_SELECTOR_NAVIGATE_FIRST: 11,
+  PAGE_SELECTOR_NAVIGATE: 12,
+  NUMBER_OF_ACTIONS: 13
+};
+
+/**
+ * Handles events specific to the PDF viewer and logs the corresponding metrics.
+ *
+ * @interface
+ */
+window.PDFMetrics = class {
+  constructor() {}
+
+  /**
+   * Call when the document is first loaded. This event serves as denominator to
+   * determine percentages of documents in which an action was taken as well as
+   * average number of each action per document.
+   */
+  onDocumentOpened() {}
+
+  /**
+   * Call when the document is rotated clockwise or counter-clockwise.
+   */
+  onRotation() {}
+
+  /**
+   * Call when the zoom mode is changed to fit a FittingType.
+   * @param {FittingType} fittingType the new FittingType.
+   */
+  onFitTo(fittingType) {}
+
+  /**
+   * Call when the bookmarks panel is opened.
+   */
+  onOpenBookmarksPanel() {}
+
+  /**
+   * Call when a bookmark is followed.
+   */
+  onFollowBookmark() {}
+
+  /**
+   * Call when the page selection is used to navigate to another page.
+   */
+  onPageSelectorNavigation() {}
+};
+
+/**
+ * Dummy implementation of PDFMetrics.
+ * This is used in print preview mode to avoid bundling the actions in the PDF
+ * viewer and the print preview in the same histogram. Also, metricsPrivate is
+ * not available in print preview.
+ * @implements {PDFMetrics}
+ */
+window.PDFMetricsDummy = class {
+  constructor() {}
+
+  /** @override */
+  onDocumentOpened() {}
+
+  /** @override */
+  onRotation() {}
+
+  /** @override */
+  onFitTo(fittingType) {}
+
+  /** @override */
+  onOpenBookmarksPanel() {}
+
+  /** @override */
+  onFollowBookmark() {}
+
+  /** @override */
+  onPageSelectorNavigation() {}
+};
+
+/**
+ * Implementation of PDFMetrics that logs the corresponding metrics to UMA
+ * through chrome.metricsPrivate.
+ * @implements {PDFMetrics}
+ */
+window.PDFMetricsImpl = class {
+  constructor() {
+    /**
+     * @private {Set}
+     */
+    this.firstEventLogged_ = new Set();
+
+    /**
+     * @private {Object}
+     */
+    this.actionsMetric_ = {
+      'metricName': 'PDF.Actions',
+      'type': chrome.metricsPrivate.MetricTypeType.HISTOGRAM_LOG,
+      'min': 1,
+      'max': UserAction.NUMBER_OF_ACTIONS,
+      'buckets': UserAction.NUMBER_OF_ACTIONS + 1
+    };
+  }
+
+  /** @override */
+  onDocumentOpened() {
+    this.logOnlyFirstTime_(UserAction.DOCUMENT_OPENED);
+  }
+
+  /** @override */
+  onRotation() {
+    this.logFirstAndTotal_(UserAction.ROTATE_FIRST, UserAction.ROTATE);
+  }
+
+  /** @override */
+  onFitTo(fittingType) {
+    if (fittingType == FittingType.FIT_TO_PAGE) {
+      this.logFirstAndTotal_(
+          UserAction.FIT_TO_PAGE_FIRST, UserAction.FIT_TO_PAGE);
+    } else if (fittingType == FittingType.FIT_TO_WIDTH) {
+      this.logFirstAndTotal_(
+          UserAction.FIT_TO_WIDTH_FIRST, UserAction.FIT_TO_WIDTH);
+    }
+    // There is no user action to do a fit-to-height, this only happens with
+    // the open param "view=FitV".
+  }
+
+  /** @override */
+  onOpenBookmarksPanel() {
+    this.logFirstAndTotal_(
+        UserAction.OPEN_BOOKMARKS_PANEL_FIRST, UserAction.OPEN_BOOKMARKS_PANEL);
+  }
+
+  /** @override */
+  onFollowBookmark() {
+    this.logFirstAndTotal_(
+        UserAction.FOLLOW_BOOKMARK_FIRST, UserAction.FOLLOW_BOOKMARK);
+  }
+
+  /** @override */
+  onPageSelectorNavigation() {
+    this.logFirstAndTotal_(
+        UserAction.PAGE_SELECTOR_NAVIGATE_FIRST,
+        UserAction.PAGE_SELECTOR_NAVIGATE);
+  }
+
+  /**
+   * @private
+   * Logs the "first" event code if it hasn't been logged by this instance yet
+   * and also log the "total" event code. This distinction allows analyzing
+   * both:
+   * - in what percentage of documents each action was taken;
+   * - how many times, on average, each action is taken on a document;
+   * @param {number} firstEventCode event code for the "first" metric.
+   * @return {number} totalEventCode event code for the "total"  metric.
+   */
+  logFirstAndTotal_(firstEventCode, totalEventCode) {
+    this.log_(totalEventCode);
+    this.logOnlyFirstTime_(firstEventCode);
+  }
+
+  /**
+   * @private
+   * Logs the given event code to chrome.metricsPrivate.
+   * @param {number} eventCode event code to log.
+   */
+  log_(eventCode) {
+    chrome.metricsPrivate.recordValue(this.actionsMetric_, eventCode);
+  }
+
+  /**
+   * @private
+   * Logs the given event code. Subsequent calls of this method with the same
+   * event code have no effect on the this PDFMetrics instance.
+   * @param {number} eventCode event code to log.
+   */
+  logOnlyFirstTime_(eventCode) {
+    if (!this.firstEventLogged_.has(eventCode)) {
+      this.log_(eventCode);
+      this.firstEventLogged_.add(eventCode);
+    }
+  }
+};
+
+window.PDFMetrics.UserAction = UserAction;
+
+}());
diff --git a/chromium/chrome/browser/resources/pdf/pdf.js b/chromium/chrome/browser/resources/pdf/pdf.js
index dcbf3d3a35e..4a8cb93199e 100644
--- a/chromium/chrome/browser/resources/pdf/pdf.js
+++ b/chromium/chrome/browser/resources/pdf/pdf.js
@@ -105,6 +105,13 @@ function PDFViewer(browserApi) {
   this.isPrintPreviewLoaded_ = false;
   this.isUserInitiatedEvent_ = true;
 
+  /**
+   * @type {PDFMetrics}
+   */
+  this.metrics =
+      (chrome.metricsPrivate ? new PDFMetricsImpl() : new PDFMetricsDummy());
+  this.metrics.onDocumentOpened();
+
   // Parse open pdf parameters.
   this.paramsParser_ =
       new OpenPDFParamsParser(this.getNamedDestination_.bind(this));
@@ -217,12 +224,23 @@ function PDFViewer(browserApi) {
     this.toolbar_.docTitle = getFilenameFromURL(this.originalUrl_);
   }
 
+  this.coordsTransformer_ =
+      new PDFCoordsTransformer(this.plugin_.postMessage.bind(this.plugin_));
+
   document.body.addEventListener('change-page', e => {
     this.viewport_.goToPage(e.detail.page);
+    if (e.detail.origin == 'bookmark')
+      this.metrics.onFollowBookmark();
+    else if (e.detail.origin == 'pageselector')
+      this.metrics.onPageSelectorNavigation();
   });
 
-  document.body.addEventListener('change-page-and-y', e => {
-    this.viewport_.goToPageAndY(e.detail.page, e.detail.y);
+  document.body.addEventListener('change-page-and-xy', e => {
+    // The coordinates received in |e| are in page coordinates and need to be
+    // transformed to screen coordinates.
+    this.coordsTransformer_.request(
+        this.goToPageAndXY_.bind(this, e.detail.origin, e.detail.page), {},
+        e.detail.page, e.detail.x, e.detail.y);
   });
 
   document.body.addEventListener('navigate', e => {
@@ -232,6 +250,11 @@ function PDFViewer(browserApi) {
     this.navigator_.navigate(e.detail.uri, disposition);
   });
 
+  document.body.addEventListener('dropdown-opened', e => {
+    if (e.detail == 'bookmarks')
+      this.metrics.onOpenBookmarksPanel();
+  });
+
   this.toolbarManager_ =
       new ToolbarManager(window, this.toolbar_, this.zoomToolbar_);
 
@@ -427,6 +450,7 @@ PDFViewer.prototype = {
    * Rotate the plugin clockwise.
    */
   rotateClockwise_: function() {
+    this.metrics.onRotation();
     this.plugin_.postMessage({type: 'rotateClockwise'});
   },
 
@@ -435,6 +459,7 @@ PDFViewer.prototype = {
    * Rotate the plugin counter-clockwise.
    */
   rotateCounterClockwise_: function() {
+    this.metrics.onRotation();
     this.plugin_.postMessage({type: 'rotateCounterclockwise'});
   },
 
@@ -444,15 +469,18 @@ PDFViewer.prototype = {
    * @param {CustomEvent} e Event received with the new FittingType as detail.
    */
   fitToChanged_: function(e) {
-    if (e.detail == FittingType.FIT_TO_PAGE) {
+    if (e.detail.fittingType == FittingType.FIT_TO_PAGE) {
       this.viewport_.fitToPage();
       this.toolbarManager_.forceHideTopToolbar();
-    } else if (e.detail == FittingType.FIT_TO_WIDTH) {
+    } else if (e.detail.fittingType == FittingType.FIT_TO_WIDTH) {
       this.viewport_.fitToWidth();
-    } else if (e.detail == FittingType.FIT_TO_HEIGHT) {
+    } else if (e.detail.fittingType == FittingType.FIT_TO_HEIGHT) {
       this.viewport_.fitToHeight();
       this.toolbarManager_.forceHideTopToolbar();
     }
+
+    if (e.detail.userInitiated)
+      this.metrics.onFitTo(e.detail.fittingType);
   },
 
   /**
@@ -503,20 +531,16 @@ PDFViewer.prototype = {
    * @param {Object} params The open params passed in the URL.
    */
   handleURLParams_: function(params) {
-    if (params.page != undefined)
-      this.viewport_.goToPage(params.page);
+    if (params.zoom)
+      this.viewport_.setZoom(params.zoom);
 
     if (params.position) {
-      // Make sure we don't cancel effect of page parameter.
-      this.viewport_.position = {
-        x: this.viewport_.position.x + params.position.x,
-        y: this.viewport_.position.y + params.position.y
-      };
+      this.viewport_.goToPageAndXY(
+          params.page ? params.page : 0, params.position.x, params.position.y);
+    } else if (params.page) {
+      this.viewport_.goToPage(params.page);
     }
 
-    if (params.zoom)
-      this.viewport_.setZoom(params.zoom);
-
     if (params.view) {
       this.isUserInitiatedEvent_ = false;
       this.zoomToolbar_.forceFit(params.view);
@@ -535,6 +559,21 @@ PDFViewer.prototype = {
 
   /**
    * @private
+   * 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
+   *     x and y to navigate to in screen coordinates.
+   */
+  goToPageAndXY_: function(origin, page, message) {
+    this.viewport_.goToPageAndXY(page, message.x, message.y);
+    if (origin == 'bookmark')
+      this.metrics.onFollowBookmark();
+  },
+
+  /**
+   * @private
    * Update the loading progress of the document in response to a progress
    * message being received from the plugin.
    * @param {number} progress the progress as a percentage.
@@ -696,6 +735,9 @@ PDFViewer.prototype = {
       case 'formFocusChange':
         this.isFormFieldFocused_ = message.data.focused;
         break;
+      case 'transformPagePointReply':
+        this.coordsTransformer_.onReplyReceived(message);
+        break;
     }
   },
 
diff --git a/chromium/chrome/browser/resources/pdf/viewport.js b/chromium/chrome/browser/resources/pdf/viewport.js
index 53e1b17ea60..709b646ff6d 100644
--- a/chromium/chrome/browser/resources/pdf/viewport.js
+++ b/chromium/chrome/browser/resources/pdf/viewport.js
@@ -798,15 +798,16 @@ Viewport.prototype = {
    * @param {number} page the index of the page to go to. zero-based.
    */
   goToPage: function(page) {
-    this.goToPageAndY(page, 0);
+    this.goToPageAndXY(page, 0, 0);
   },
 
   /**
    * Go to the given y position in the given page index.
    * @param {number} page the index of the page to go to. zero-based.
+   * @param {number} x the x position in the page to go to.
    * @param {number} y the y position in the page to go to.
    */
-  goToPageAndY: function(page, y) {
+  goToPageAndXY: function(page, x, y) {
     this.mightZoom_(() => {
       if (this.pageDimensions_.length === 0)
         return;
@@ -822,7 +823,7 @@ Viewport.prototype = {
       if (!this.isPagedMode())
         toolbarOffset = this.topToolbarHeight_;
       this.position = {
-        x: dimensions.x * this.zoom,
+        x: (dimensions.x + x) * this.zoom,
         y: (dimensions.y + y) * this.zoom - toolbarOffset
       };
       this.updateViewport_();