Add printRequest()

Adds printRequested() signal for web content. This signal
is emitted on javascript window.print().

This change updates also qt printview manager implementation,
fixes a corner case and warnings about ipc unconsumed attachments.

Task-number: QTBUG-69237
Task-number: QTBUG-53745
Change-Id: I0c47b732e27e929ac6db237fb562b7d5f9b959c2
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

13 files changed, 244 insertions, 102 deletions

diff --git a/src/core/printing/print_view_manager_base_qt.cpp b/src/core/printing/print_view_manager_base_qt.cpp
index facc4ff84..6c67adbc7 100644
--- a/src/core/printing/print_view_manager_base_qt.cpp
+++ b/src/core/printing/print_view_manager_base_qt.cpp
@@ -72,15 +72,13 @@ namespace QtWebEngineCore {
 
 PrintViewManagerBaseQt::PrintViewManagerBaseQt(content::WebContents *contents)
     : printing::PrintManager(contents)
-    , cookie_(0)
     , m_isInsideInnerMessageLoop(false)
-#if !defined(OS_MACOSX)
-    , m_isExpectingFirstPage(false)
-#endif
     , m_didPrintingSucceed(false)
     , m_printerQueriesQueue(WebEngineContext::current()->getPrintJobManager()->queue())
+    , m_printingRFH(nullptr)
 {
     // FIXME: Check if this needs to be executed async:
+    // TODO: Add isEnabled to profile
     PrintViewManagerBaseQt::UpdatePrintingEnabled();
 }
 
@@ -90,8 +88,15 @@ PrintViewManagerBaseQt::~PrintViewManagerBaseQt()
     DisconnectFromCurrentPrintJob();
 }
 
+void PrintViewManagerBaseQt::SetPrintingRFH(content::RenderFrameHost *rfh)
+{
+    DCHECK(!m_printingRFH);
+    m_printingRFH = rfh;
+}
+
 void PrintViewManagerBaseQt::UpdatePrintingEnabled()
 {
+    DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
     bool enabled = false;
 #if QT_CONFIG(webengine_printing_and_pdf)
     enabled = true;
@@ -112,24 +117,19 @@ base::string16 PrintViewManagerBaseQt::RenderSourceName()
      return toString16(QLatin1String(""));
 }
 
-bool PrintViewManagerBaseQt::PrintDocument(printing::PrintedDocument *document,
-                                           const scoped_refptr<base::RefCountedBytes> &print_data,
+void PrintViewManagerBaseQt::PrintDocument(printing::PrintedDocument *document,
+                                           const scoped_refptr<base::RefCountedMemory> &print_data,
                                            const gfx::Size &page_size,
                                            const gfx::Rect &content_area,
                                            const gfx::Point &offsets)
 {
     std::unique_ptr<printing::PdfMetafileSkia> metafile =
             std::make_unique<printing::PdfMetafileSkia>();
-    if (!metafile->InitFromData(print_data->front(), print_data->size())) {
-        NOTREACHED() << "Invalid metafile";
-        web_contents()->Stop();
-        return false;
-    }
+    CHECK(metafile->InitFromData(print_data->front(), print_data->size()));
 
     // Update the rendered document. It will send notifications to the listener.
     document->SetDocument(std::move(metafile), page_size, content_area);
     ShouldQuitFromInnerMessageLoop();
-    return true;
 }
 
 printing::PrintedDocument *PrintViewManagerBaseQt::GetDocument(int cookie)
@@ -147,7 +147,8 @@ printing::PrintedDocument *PrintViewManagerBaseQt::GetDocument(int cookie)
 }
 
 // IPC handlers
-void PrintViewManagerBaseQt::OnDidPrintDocument(const PrintHostMsg_DidPrintDocument_Params &params)
+void PrintViewManagerBaseQt::OnDidPrintDocument(content::RenderFrameHost* /*render_frame_host*/,
+                                                const PrintHostMsg_DidPrintDocument_Params &params)
 {
     printing::PrintedDocument *document = GetDocument(params.document_cookie);
     if (!document)
@@ -167,10 +168,10 @@ void PrintViewManagerBaseQt::OnDidPrintDocument(const PrintHostMsg_DidPrintDocum
         web_contents()->Stop();
         return;
     }
-    scoped_refptr<base::RefCountedBytes> bytes =
-            base::MakeRefCounted<base::RefCountedBytes>(
-                    reinterpret_cast<const unsigned char*>(shared_buf->memory()), content.data_size);
-    PrintDocument(document, bytes, params.page_size, params.content_area, params.physical_offsets);
+    auto data = base::MakeRefCounted<base::RefCountedSharedMemory>(
+        std::move(shared_buf), content.data_size);
+    PrintDocument(document, data, params.page_size, params.content_area,
+                  params.physical_offsets);
 }
 
 void PrintViewManagerBaseQt::OnShowInvalidPrinterSettingsError()
@@ -182,12 +183,16 @@ void PrintViewManagerBaseQt::DidStartLoading()
     UpdatePrintingEnabled();
 }
 
+// Note: In PrintViewManagerQt we always initiate printing with PrintMsg_InitiatePrintPreview
+// so m_printingRFH is never set and used at the moment.
 void PrintViewManagerBaseQt::RenderFrameDeleted(content::RenderFrameHost *render_frame_host)
 {
     // Terminates or cancels the print job if one was pending.
-    if (render_frame_host != web_contents()->GetMainFrame())
+    if (render_frame_host != m_printingRFH)
         return;
 
+    m_printingRFH = nullptr;
+
     PrintManager::PrintingRenderFrameDeleted();
     ReleasePrinterQuery();
 
@@ -203,12 +208,20 @@ void PrintViewManagerBaseQt::RenderFrameDeleted(content::RenderFrameHost *render
     }
 }
 
-bool PrintViewManagerBaseQt::OnMessageReceived(const IPC::Message& message, content::RenderFrameHost* render_frame_host)
+bool PrintViewManagerBaseQt::OnMessageReceived(const IPC::Message& message,
+                                               content::RenderFrameHost* render_frame_host)
 {
     bool handled = true;
-    IPC_BEGIN_MESSAGE_MAP(PrintViewManagerBaseQt, message)
+    IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(PrintViewManagerBaseQt, message, render_frame_host)
         IPC_MESSAGE_HANDLER(PrintHostMsg_DidPrintDocument, OnDidPrintDocument)
-        IPC_MESSAGE_HANDLER(PrintHostMsg_ShowInvalidPrinterSettingsError, OnShowInvalidPrinterSettingsError);
+        IPC_MESSAGE_UNHANDLED(handled = false)
+    IPC_END_MESSAGE_MAP()
+    if (handled)
+        return true;
+    handled = true;
+    IPC_BEGIN_MESSAGE_MAP(PrintViewManagerBaseQt, message)
+        IPC_MESSAGE_HANDLER(PrintHostMsg_ShowInvalidPrinterSettingsError,
+                            OnShowInvalidPrinterSettingsError);
         IPC_MESSAGE_UNHANDLED(handled = false)
     IPC_END_MESSAGE_MAP()
     return handled || PrintManager::OnMessageReceived(message, render_frame_host);
@@ -225,7 +238,7 @@ void PrintViewManagerBaseQt::Observe(int type,
 void PrintViewManagerBaseQt::OnNotifyPrintJobEvent(const printing::JobEventDetails& event_details)
 {
     switch (event_details.type()) {
-    case printing::JobEventDetails::FAILED:
+    case printing::JobEventDetails::FAILED: {
         TerminatePrintJob(true);
 
         content::NotificationService::current()->Notify(
@@ -233,21 +246,26 @@ void PrintViewManagerBaseQt::OnNotifyPrintJobEvent(const printing::JobEventDetai
                 content::Source<content::WebContents>(web_contents()),
                 content::NotificationService::NoDetails());
         break;
+    }
     case printing::JobEventDetails::USER_INIT_DONE:
     case printing::JobEventDetails::DEFAULT_INIT_DONE:
-    case printing::JobEventDetails::USER_INIT_CANCELED:
+    case printing::JobEventDetails::USER_INIT_CANCELED: {
         NOTREACHED();
         break;
-    case printing::JobEventDetails::ALL_PAGES_REQUESTED:
+    }
+    case printing::JobEventDetails::ALL_PAGES_REQUESTED: {
+        ShouldQuitFromInnerMessageLoop();
         break;
+    }
     case printing::JobEventDetails::NEW_DOC:
 #if defined(OS_WIN)
     case printing::JobEventDetails::PAGE_DONE:
 #endif
-    case printing::JobEventDetails::DOC_DONE:
+    case printing::JobEventDetails::DOC_DONE: {
         // Don't care about the actual printing process.
         break;
-    case printing::JobEventDetails::JOB_DONE:
+    }
+    case printing::JobEventDetails::JOB_DONE: {
         // Printing is done, we don't need it anymore.
         // print_job_->is_job_pending() may still be true, depending on the order
         // of object registration.
@@ -259,6 +277,7 @@ void PrintViewManagerBaseQt::OnNotifyPrintJobEvent(const printing::JobEventDetai
                 content::Source<content::WebContents>(web_contents()),
                 content::NotificationService::NoDetails());
         break;
+    }
     default:
         NOTREACHED();
         break;
@@ -273,6 +292,12 @@ bool PrintViewManagerBaseQt::RenderAllMissingPagesNow()
     if (!m_printJob.get() || !m_printJob->is_job_pending())
       return false;
 
+    // Is the document already complete?
+    if (m_printJob->document() && m_printJob->document()->IsComplete()) {
+        m_didPrintingSucceed = true;
+        return true;
+    }
+
     // We can't print if there is no renderer.
     if (!web_contents() ||
         !web_contents()->GetRenderViewHost() ||
@@ -280,12 +305,6 @@ bool PrintViewManagerBaseQt::RenderAllMissingPagesNow()
       return false;
     }
 
-    // Is the document already complete?
-    if (m_printJob->document() && m_printJob->document()->IsComplete()) {
-      m_didPrintingSucceed = true;
-      return true;
-    }
-
     // WebContents is either dying or a second consecutive request to print
     // happened before the first had time to finish. We need to render all the
     // pages in an hurry if a print_job_ is still pending. No need to wait for it
@@ -319,7 +338,7 @@ void PrintViewManagerBaseQt::ShouldQuitFromInnerMessageLoop()
         m_isInsideInnerMessageLoop) {
       // We are in a message loop created by RenderAllMissingPagesNow. Quit from
       // it.
-      base::MessageLoop::current()->QuitWhenIdleClosure();
+      base::RunLoop::QuitCurrentWhenIdleDeprecated();
       m_isInsideInnerMessageLoop = false;
     }
 }
@@ -344,7 +363,7 @@ bool PrintViewManagerBaseQt::CreateNewPrintJob(printing::PrintJobWorkerOwner* jo
     if (!job)
         return false;
 
-    m_printJob = new printing::PrintJob();
+    m_printJob = base::MakeRefCounted<printing::PrintJob>();
     m_printJob->Initialize(job, RenderSourceName(), number_pages_);
     m_registrar.Add(this, chrome::NOTIFICATION_PRINT_JOB_EVENT,
                     content::Source<printing::PrintJob>(m_printJob.get()));
@@ -369,9 +388,6 @@ void PrintViewManagerBaseQt::DisconnectFromCurrentPrintJob()
         // DO NOT wait for the job to finish.
         ReleasePrintJob();
     }
-#if !defined(OS_MACOSX)
-    m_isExpectingFirstPage = true;
-#endif
 }
 
 void PrintViewManagerBaseQt::TerminatePrintJob(bool cancel)
@@ -397,13 +413,18 @@ void PrintViewManagerBaseQt::TerminatePrintJob(bool cancel)
 
 void PrintViewManagerBaseQt::ReleasePrintJob()
 {
-    content::RenderFrameHost *rfh = web_contents() ? web_contents()->GetMainFrame() : nullptr;
+    content::RenderFrameHost* rfh = m_printingRFH;
+    m_printingRFH = nullptr;
 
     if (!m_printJob.get())
         return;
 
-    if (rfh)
-        rfh->Send(new PrintMsg_PrintingDone(rfh->GetRoutingID(), m_didPrintingSucceed));
+    if (rfh) {
+        auto msg = std::make_unique<PrintMsg_PrintingDone>(rfh->GetRoutingID(),
+                                                           m_didPrintingSucceed);
+        rfh->Send(msg.release());
+    }
+
 
     m_registrar.Remove(this, chrome::NOTIFICATION_PRINT_JOB_EVENT,
                        content::Source<printing::PrintJob>(m_printJob.get()));
@@ -411,7 +432,6 @@ void PrintViewManagerBaseQt::ReleasePrintJob()
     m_printJob = nullptr;
 }
 
-
 bool PrintViewManagerBaseQt::RunInnerMessageLoop() {
   // This value may actually be too low:
   //
@@ -426,19 +446,18 @@ bool PrintViewManagerBaseQt::RunInnerMessageLoop() {
   // memory-bound.
   static const int kPrinterSettingsTimeout = 60000;
   base::OneShotTimer quit_timer;
-  base::RunLoop runLoop;
+  base::RunLoop run_loop;
   quit_timer.Start(FROM_HERE,
                    base::TimeDelta::FromMilliseconds(kPrinterSettingsTimeout),
-                   runLoop.QuitWhenIdleClosure());
+                   run_loop.QuitWhenIdleClosure());
 
   m_isInsideInnerMessageLoop = true;
 
   // Need to enable recursive task.
   {
-      m_quitClosure = runLoop.QuitClosure();
-      base::MessageLoop* loop = base::MessageLoop::current();
-      base::MessageLoop::ScopedNestableTaskAllower allowNested(loop);
-      runLoop.Run();
+      base::MessageLoop::ScopedNestableTaskAllower allow(
+             base::MessageLoop::current());
+      run_loop.Run();
   }
 
   bool success = true;
diff --git a/src/core/printing/print_view_manager_base_qt.h b/src/core/printing/print_view_manager_base_qt.h
index 0d86fcf90..eb4302fe8 100644
--- a/src/core/printing/print_view_manager_base_qt.h
+++ b/src/core/printing/print_view_manager_base_qt.h
@@ -44,7 +44,7 @@
 #ifndef PRINT_VIEW_MANAGER_BASE_QT_H
 #define PRINT_VIEW_MANAGER_BASE_QT_H
 
-#include "base/memory/ref_counted.h"
+#include "base/memory/ref_counted_memory.h"
 #include "base/strings/string16.h"
 #include "components/prefs/pref_member.h"
 #include "components/printing/browser/print_manager.h"
@@ -87,6 +87,8 @@ public:
 protected:
     explicit PrintViewManagerBaseQt(content::WebContents*);
 
+    void SetPrintingRFH(content::RenderFrameHost* rfh);
+
     // content::WebContentsObserver implementation.
     // Cancels the print job.
     void NavigationStopped() override;
@@ -97,16 +99,13 @@ protected:
                            content::RenderFrameHost* render_frame_host) override;
 
     // IPC Message handlers.
-    void OnDidPrintDocument(const PrintHostMsg_DidPrintDocument_Params& params);
+    void OnDidPrintDocument(content::RenderFrameHost* render_frame_host,
+                            const PrintHostMsg_DidPrintDocument_Params& params);
     void OnShowInvalidPrinterSettingsError();
 
     // Processes a NOTIFY_PRINT_JOB_EVENT notification.
     void OnNotifyPrintJobEvent(const printing::JobEventDetails& event_details);
 
-    int number_pages_;  // Number of pages to print in the print job.
-    int cookie_;
-    std::unique_ptr<base::DictionaryValue> m_printSettings;
-
     // content::NotificationObserver implementation.
     void Observe(int,
                  const content::NotificationSource&,
@@ -130,8 +129,8 @@ protected:
     // Starts printing a document with data given in |print_data|. |print_data|
     // must successfully initialize a metafile. |document| is the printed
     // document associated with the print job. Returns true if successful.
-    bool PrintDocument(printing::PrintedDocument *document,
-                       const scoped_refptr<base::RefCountedBytes> &print_data,
+    void PrintDocument(printing::PrintedDocument *document,
+                       const scoped_refptr<base::RefCountedMemory> &print_data,
                        const gfx::Size &page_size,
                        const gfx::Rect &content_area,
                        const gfx::Point &offsets);
@@ -155,21 +154,17 @@ protected:
 private:
     // Helper method for UpdatePrintingEnabled().
     void SendPrintingEnabled(bool enabled, content::RenderFrameHost* rfh);
+    // content::WebContentsObserver implementation.
+    void DidStartLoading() override;
 
+private:
     content::NotificationRegistrar m_registrar;
     scoped_refptr<printing::PrintJob> m_printJob;
-    // Closure for quitting nested message loop.
-    base::Closure m_quitClosure;
-
     bool m_isInsideInnerMessageLoop;
-#if !defined(OS_MACOSX)
-    bool m_isExpectingFirstPage;
-#endif
     bool m_didPrintingSucceed;
     scoped_refptr<printing::PrintQueriesQueue> m_printerQueriesQueue;
-    // content::WebContentsObserver implementation.
-    void DidStartLoading() override;
-
+    // The current RFH that is printing with a system printing dialog.
+    content::RenderFrameHost* m_printingRFH;
     DISALLOW_COPY_AND_ASSIGN(PrintViewManagerBaseQt);
 };
 
diff --git a/src/core/printing/print_view_manager_qt.cpp b/src/core/printing/print_view_manager_qt.cpp
index bb176d687..fffc91631 100644
--- a/src/core/printing/print_view_manager_qt.cpp
+++ b/src/core/printing/print_view_manager_qt.cpp
@@ -45,6 +45,7 @@
 
 #include "type_conversion.h"
 #include "web_engine_context.h"
+#include "web_contents_view_qt.h"
 
 #include <QtGui/qpagelayout.h>
 #include <QtGui/qpagesize.h>
@@ -66,6 +67,7 @@
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(QtWebEngineCore::PrintViewManagerQt);
 
 namespace {
+
 static const qreal kMicronsToMillimeter = 1000.0f;
 
 static std::vector<char>
@@ -85,11 +87,10 @@ GetStdVectorFromHandle(base::SharedMemoryHandle handle, uint32_t data_size)
 static scoped_refptr<base::RefCountedBytes>
 GetBytesFromHandle(base::SharedMemoryHandle handle, uint32_t data_size)
 {
-     std::unique_ptr<base::SharedMemory> shared_buf(
-                 new base::SharedMemory(handle, true));
+    std::unique_ptr<base::SharedMemory> shared_buf(new base::SharedMemory(handle, true));
 
     if (!shared_buf->Map(data_size)) {
-       return NULL;
+        return nullptr;
     }
 
     unsigned char* data = static_cast<unsigned char*>(shared_buf->memory());
@@ -99,9 +100,8 @@ GetBytesFromHandle(base::SharedMemoryHandle handle, uint32_t data_size)
 
 // Write the PDF file to disk.
 static void SavePdfFile(scoped_refptr<base::RefCountedBytes> data,
-                        const base::FilePath& path,
-                        const QtWebEngineCore::PrintViewManagerQt::PrintToPDFFileCallback
-                                &saveCallback)
+                        const base::FilePath &path,
+                        const QtWebEngineCore::PrintViewManagerQt::PrintToPDFFileCallback &saveCallback)
 {
     base::AssertBlockingAllowed();
     DCHECK_GT(data->size(), 0U);
@@ -197,6 +197,19 @@ static base::DictionaryValue *createPrintSettingsFromQPageLayout(const QPageLayo
 
 namespace QtWebEngineCore {
 
+struct PrintViewManagerQt::FrameDispatchHelper {
+    PrintViewManagerQt* m_manager;
+    content::RenderFrameHost* m_renderFrameHost;
+
+    bool Send(IPC::Message* msg) {
+        return m_renderFrameHost->Send(msg);
+    }
+
+    void OnSetupScriptedPrintPreview(IPC::Message* reply_msg) {
+        m_manager->OnSetupScriptedPrintPreview(m_renderFrameHost, reply_msg);
+    }
+};
+
 PrintViewManagerQt::~PrintViewManagerQt()
 {
 }
@@ -211,8 +224,7 @@ void PrintViewManagerQt::PrintToPDFFileWithCallback(const QPageLayout &pageLayou
         return;
 
     if (m_printSettings || !filePath.length()) {
-                content::BrowserThread::PostTask(content::BrowserThread::UI,
-                                         FROM_HERE,
+        content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
                                          base::Bind(callback, false));
         return;
     }
@@ -220,8 +232,7 @@ void PrintViewManagerQt::PrintToPDFFileWithCallback(const QPageLayout &pageLayou
     m_pdfOutputPath = toFilePath(filePath);
     m_pdfSaveCallback = callback;
     if (!PrintToPDFInternal(pageLayout, printInColor)) {
-        content::BrowserThread::PostTask(content::BrowserThread::UI,
-                                         FROM_HERE,
+        content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
                                          base::Bind(callback, false));
         resetPdfState();
     }
@@ -237,9 +248,8 @@ void PrintViewManagerQt::PrintToPDFWithCallback(const QPageLayout &pageLayout,
 
     // If there already is a pending print in progress, don't try starting another one.
     if (m_printSettings) {
-            content::BrowserThread::PostTask(content::BrowserThread::UI,
-                                             FROM_HERE,
-                                             base::Bind(callback, std::vector<char>()));
+        content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE,
+                                         base::Bind(callback, std::vector<char>()));
         return;
     }
 
@@ -261,12 +271,27 @@ bool PrintViewManagerQt::PrintToPDFInternal(const QPageLayout &pageLayout,
         return false;
 
     m_printSettings.reset(createPrintSettingsFromQPageLayout(pageLayout, useCustomMargins));
-    m_printSettings->SetBoolean(printing::kSettingShouldPrintBackgrounds
-        , web_contents()->GetRenderViewHost()->GetWebkitPreferences().should_print_backgrounds);
+    m_printSettings->SetBoolean(printing::kSettingShouldPrintBackgrounds,
+                                web_contents()->GetRenderViewHost()->
+                                GetWebkitPreferences().should_print_backgrounds);
     m_printSettings->SetInteger(printing::kSettingColor,
                                 printInColor ? printing::COLOR : printing::GRAYSCALE);
-    return web_contents()->GetMainFrame()->Send(
-                new PrintMsg_InitiatePrintPreview(web_contents()->GetMainFrame()->GetRoutingID(), false));
+
+    if (web_contents()->ShowingInterstitialPage() || web_contents()->IsCrashed())
+        return false;
+
+    content::RenderFrameHost* rfh = web_contents()->GetMainFrame();
+    auto message = std::make_unique<PrintMsg_InitiatePrintPreview>(
+                rfh->GetRoutingID(), false);
+
+    DCHECK(!m_printPreviewRfh);
+
+    if (!rfh->Send(message.release())) {
+        return false;
+    }
+
+    m_printPreviewRfh = rfh;
+    return true;
 }
 
 #endif // QT_CONFIG(webengine_printing_and_pdf)
@@ -274,26 +299,42 @@ bool PrintViewManagerQt::PrintToPDFInternal(const QPageLayout &pageLayout,
 // PrintedPagesSource implementation.
 base::string16 PrintViewManagerQt::RenderSourceName()
 {
-     return toString16(QLatin1String(""));
+    return base::string16();
 }
 
 PrintViewManagerQt::PrintViewManagerQt(content::WebContents *contents)
     : PrintViewManagerBaseQt(contents)
+    , m_printPreviewRfh(nullptr)
 {
 
 }
 
 // content::WebContentsObserver implementation.
-bool PrintViewManagerQt::OnMessageReceived(const IPC::Message& message, content::RenderFrameHost* render_frame_host)
+bool PrintViewManagerQt::OnMessageReceived(const IPC::Message& message,
+                                           content::RenderFrameHost* render_frame_host)
 {
+    FrameDispatchHelper helper = {this, render_frame_host};
     bool handled = true;
-    IPC_BEGIN_MESSAGE_MAP(PrintViewManagerQt, message)
-      IPC_MESSAGE_HANDLER(PrintHostMsg_DidShowPrintDialog, OnDidShowPrintDialog)
-      IPC_MESSAGE_HANDLER(PrintHostMsg_RequestPrintPreview, OnRequestPrintPreview)
-      IPC_MESSAGE_HANDLER(PrintHostMsg_MetafileReadyForPrinting, OnMetafileReadyForPrinting);
-      IPC_MESSAGE_UNHANDLED(handled = false)
+    IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(PrintViewManagerQt, message, render_frame_host);
+        IPC_MESSAGE_HANDLER(PrintHostMsg_DidShowPrintDialog, OnDidShowPrintDialog)
+        IPC_MESSAGE_HANDLER(PrintHostMsg_RequestPrintPreview, OnRequestPrintPreview)
+        IPC_MESSAGE_HANDLER(PrintHostMsg_MetafileReadyForPrinting, OnMetafileReadyForPrinting);
+        IPC_MESSAGE_HANDLER(PrintHostMsg_DidPreviewPage, OnDidPreviewPage)
+        IPC_MESSAGE_FORWARD_DELAY_REPLY(
+                PrintHostMsg_SetupScriptedPrintPreview, &helper,
+                FrameDispatchHelper::OnSetupScriptedPrintPreview)
+        IPC_MESSAGE_HANDLER(PrintHostMsg_ShowScriptedPrintPreview,
+                                       OnShowScriptedPrintPreview)
+        IPC_MESSAGE_UNHANDLED(handled = false)
     IPC_END_MESSAGE_MAP()
-    return handled || PrintManager::OnMessageReceived(message, render_frame_host);
+    return handled || PrintViewManagerBaseQt::OnMessageReceived(message, render_frame_host);
+}
+
+void PrintViewManagerQt::RenderFrameDeleted(content::RenderFrameHost *render_frame_host)
+{
+    if (render_frame_host == m_printPreviewRfh)
+        PrintPreviewDone();
+    PrintViewManagerBaseQt::RenderFrameDeleted(render_frame_host);
 }
 
 void PrintViewManagerQt::resetPdfState()
@@ -309,9 +350,9 @@ void PrintViewManagerQt::resetPdfState()
 void PrintViewManagerQt::OnRequestPrintPreview(
     const PrintHostMsg_RequestPrintPreview_Params &/*params*/)
 {
-    auto *rfh = web_contents()->GetMainFrame();
-    rfh->Send(new PrintMsg_PrintPreview(rfh->GetRoutingID(), *m_printSettings));
-    rfh->Send(new PrintMsg_ClosePrintPreviewDialog(rfh->GetRoutingID()));
+    m_printPreviewRfh->Send(new PrintMsg_PrintPreview(m_printPreviewRfh->GetRoutingID(),
+                                                      *m_printSettings));
+    PrintPreviewDone();
 }
 
 void PrintViewManagerQt::OnMetafileReadyForPrinting(
@@ -359,6 +400,7 @@ void PrintViewManagerQt::NavigationStopped()
                                          base::Bind(m_pdfPrintCallback, std::vector<char>()));
     }
     resetPdfState();
+    PrintViewManagerBaseQt::NavigationStopped();
 }
 
 void PrintViewManagerQt::RenderProcessGone(base::TerminationStatus status)
@@ -372,5 +414,39 @@ void PrintViewManagerQt::RenderProcessGone(base::TerminationStatus status)
     resetPdfState();
 }
 
+void PrintViewManagerQt::OnDidPreviewPage(const PrintHostMsg_DidPreviewPage_Params &params)
+{
+    // just consume the message, this is just for sending 'page-preview-ready' for webui
+}
+
+void PrintViewManagerQt::OnSetupScriptedPrintPreview(content::RenderFrameHost* rfh,
+                                                     IPC::Message* reply_msg)
+{
+    // ignore the scripted print
+    rfh->Send(reply_msg);
+
+    content::WebContentsView *view = static_cast<content::WebContentsImpl*>(web_contents())->GetView();
+    WebContentsAdapterClient *client = WebContentsViewQt::from(view)->client();
+
+    if (!client)
+        return;
+
+    // close preview
+    rfh->Send(new PrintMsg_ClosePrintPreviewDialog(rfh->GetRoutingID()));
+
+    client->printRequested();
+}
+
+void PrintViewManagerQt::OnShowScriptedPrintPreview(content::RenderFrameHost* rfh,
+                                                    bool source_is_modifiable)
+{
+    // ignore for now
+}
+
+void PrintViewManagerQt::PrintPreviewDone() {
+    m_printPreviewRfh->Send(new PrintMsg_ClosePrintPreviewDialog(
+                                m_printPreviewRfh->GetRoutingID()));
+    m_printPreviewRfh = nullptr;
+}
 
 } // namespace QtWebEngineCore
diff --git a/src/core/printing/print_view_manager_qt.h b/src/core/printing/print_view_manager_qt.h
index c181d9063..c71ec4a61 100644
--- a/src/core/printing/print_view_manager_qt.h
+++ b/src/core/printing/print_view_manager_qt.h
@@ -51,6 +51,7 @@
 #include "base/strings/string16.h"
 #include "components/prefs/pref_member.h"
 #include "components/printing/browser/print_manager.h"
+#include "components/printing/common/print_messages.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ -77,7 +78,7 @@ QT_END_NAMESPACE
 
 namespace QtWebEngineCore {
 class PrintViewManagerQt
-        : PrintViewManagerBaseQt
+        : public PrintViewManagerBaseQt
         , public content::WebContentsUserData<PrintViewManagerQt>
 {
 public:
@@ -111,28 +112,38 @@ protected:
     // content::WebContentsObserver implementation.
     bool OnMessageReceived(const IPC::Message& message,
                            content::RenderFrameHost* render_frame_host) override;
+    void RenderFrameDeleted(content::RenderFrameHost* render_frame_host) override;
 
     // IPC handlers
     void OnDidShowPrintDialog();
     void OnRequestPrintPreview(const PrintHostMsg_RequestPrintPreview_Params&);
     void OnMetafileReadyForPrinting(const PrintHostMsg_DidPreviewDocument_Params& params);
+    void OnSetupScriptedPrintPreview(content::RenderFrameHost* rfh,
+                                      IPC::Message* reply_msg);
+    void OnDidPreviewPage(const PrintHostMsg_DidPreviewPage_Params& params);
+    void OnShowScriptedPrintPreview(content::RenderFrameHost* rfh,
+                                    bool source_is_modifiable);
+
 
 #if QT_CONFIG(webengine_printing_and_pdf)
     bool PrintToPDFInternal(const QPageLayout &, bool printInColor, bool useCustomMargins = true);
 #endif
 
-    base::FilePath m_pdfOutputPath;
-    PrintToPDFCallback m_pdfPrintCallback;
-    PrintToPDFFileCallback m_pdfSaveCallback;
-
 private:
-    friend class content::WebContentsUserData<PrintViewManagerQt>;
-
     void resetPdfState();
-
     // content::WebContentsObserver implementation.
     void DidStartLoading() override;
+    void PrintPreviewDone();
+
+private:
+    content::RenderFrameHost *m_printPreviewRfh;
+    base::FilePath m_pdfOutputPath;
+    PrintToPDFCallback m_pdfPrintCallback;
+    PrintToPDFFileCallback m_pdfSaveCallback;
+    std::unique_ptr<base::DictionaryValue> m_printSettings;
+    friend class content::WebContentsUserData<PrintViewManagerQt>;
     DISALLOW_COPY_AND_ASSIGN(PrintViewManagerQt);
+    struct FrameDispatchHelper;
 };
 
 } // namespace QtWebEngineCore
diff --git a/src/core/renderer/print_web_view_helper_delegate_qt.cpp b/src/core/renderer/print_web_view_helper_delegate_qt.cpp
index 79d86b00f..e693cf096 100644
--- a/src/core/renderer/print_web_view_helper_delegate_qt.cpp
+++ b/src/core/renderer/print_web_view_helper_delegate_qt.cpp
@@ -53,7 +53,7 @@ PrintWebViewHelperDelegateQt::~PrintWebViewHelperDelegateQt()
 
 bool PrintWebViewHelperDelegateQt::CancelPrerender(content::RenderFrame *)
 {
-    return true;
+    return false;
 }
 
 blink::WebElement PrintWebViewHelperDelegateQt::GetPdfElement(blink::WebLocalFrame* frame)
@@ -63,7 +63,7 @@ blink::WebElement PrintWebViewHelperDelegateQt::GetPdfElement(blink::WebLocalFra
 
 bool PrintWebViewHelperDelegateQt::IsPrintPreviewEnabled()
 {
-    return false;
+    return true;
 }
 
 bool PrintWebViewHelperDelegateQt::OverridePrint(blink::WebLocalFrame* frame)
diff --git a/src/core/web_contents_adapter_client.h b/src/core/web_contents_adapter_client.h
index 851a6122f..6fd29ec61 100644
--- a/src/core/web_contents_adapter_client.h
+++ b/src/core/web_contents_adapter_client.h
@@ -472,6 +472,7 @@ public:
     virtual const QObject *holdingQObject() const = 0;
     virtual void setToolTip(const QString& toolTipText) = 0;
     virtual ClientType clientType() = 0;
+    virtual void printRequested() = 0;
 
     virtual ProfileAdapter *profileAdapter() = 0;
     virtual WebContentsAdapter* webContentsAdapter() = 0;
diff --git a/src/webengine/api/qquickwebengineview.cpp b/src/webengine/api/qquickwebengineview.cpp
index aaa8d58c5..f24ba1d7d 100644
--- a/src/webengine/api/qquickwebengineview.cpp
+++ b/src/webengine/api/qquickwebengineview.cpp
@@ -640,6 +640,14 @@ WebContentsAdapter *QQuickWebEngineViewPrivate::webContentsAdapter()
     return adapter.data();
 }
 
+void QQuickWebEngineViewPrivate::printRequested()
+{
+    Q_Q(QQuickWebEngineView);
+    QTimer::singleShot(0, q, [q]() {
+        Q_EMIT q->printRequested();
+    });
+}
+
 WebEngineSettings *QQuickWebEngineViewPrivate::webEngineSettings() const
 {
     return m_settings->d_ptr.data();
diff --git a/src/webengine/api/qquickwebengineview_p.h b/src/webengine/api/qquickwebengineview_p.h
index d400fc75e..f60fdcddf 100644
--- a/src/webengine/api/qquickwebengineview_p.h
+++ b/src/webengine/api/qquickwebengineview_p.h
@@ -549,6 +549,7 @@ Q_SIGNALS:
     Q_REVISION(7) void inspectedViewChanged();
     Q_REVISION(7) void devToolsViewChanged();
     Q_REVISION(7) void registerProtocolHandlerRequested(const QWebEngineRegisterProtocolHandlerRequest &request);
+    Q_REVISION(8) void printRequested();
 
 #if QT_CONFIG(webengine_testsupport)
     void testSupportChanged();
diff --git a/src/webengine/api/qquickwebengineview_p_p.h b/src/webengine/api/qquickwebengineview_p_p.h
index 7e5d1e64f..b030b2a29 100644
--- a/src/webengine/api/qquickwebengineview_p_p.h
+++ b/src/webengine/api/qquickwebengineview_p_p.h
@@ -155,6 +155,7 @@ public:
 
     QtWebEngineCore::ProfileAdapter *profileAdapter() override;
     QtWebEngineCore::WebContentsAdapter *webContentsAdapter() override;
+    void printRequested() override;
 
     void updateAction(QQuickWebEngineView::WebAction) const;
     void adoptWebContents(QtWebEngineCore::WebContentsAdapter *webContents);
diff --git a/src/webengine/doc/src/webengineview_lgpl.qdoc b/src/webengine/doc/src/webengineview_lgpl.qdoc
index 741dee2f7..cc826a0d9 100644
--- a/src/webengine/doc/src/webengineview_lgpl.qdoc
+++ b/src/webengine/doc/src/webengineview_lgpl.qdoc
@@ -1462,3 +1462,13 @@
 
     \sa WebEngineAction
 */
+
+/*!
+    \qmlsignal WebEngineView::printRequest
+    \since QtWebEngine 1.8
+
+    This signal is emitted when the JavaScript \c{window.print()} method is called.
+    Typically, the signal handler can simply call printToPdf().
+
+    \sa printToPdf
+*/
diff --git a/src/webenginewidgets/api/qwebenginepage.cpp b/src/webenginewidgets/api/qwebenginepage.cpp
index 16a9c138d..5b42b871a 100644
--- a/src/webenginewidgets/api/qwebenginepage.cpp
+++ b/src/webenginewidgets/api/qwebenginepage.cpp
@@ -739,6 +739,16 @@ QWebEnginePage::QWebEnginePage(QObject* parent)
 }
 
 /*!
+    \fn void QWebEnginePage::printRequested()
+    \since 5.12
+
+    This signal is emitted when the JavaScript \c{window.print()} method is called.
+    Typically, the signal handler can simply call printToPdf().
+
+    \sa printToPdf()
+*/
+
+/*!
     \enum QWebEnginePage::RenderProcessTerminationStatus
     \since 5.6
 
@@ -1751,6 +1761,14 @@ void QWebEnginePagePrivate::setToolTip(const QString &toolTipText)
         view->setToolTip(wrappedTip);
 }
 
+void QWebEnginePagePrivate::printRequested()
+{
+    Q_Q(QWebEnginePage);
+    QTimer::singleShot(0, q, [q](){
+        Q_EMIT q->printRequested();
+    });
+}
+
 #if QT_CONFIG(menu)
 QMenu *QWebEnginePage::createStandardContextMenu()
 {
diff --git a/src/webenginewidgets/api/qwebenginepage.h b/src/webenginewidgets/api/qwebenginepage.h
index 3e5e083df..b8bf61700 100644
--- a/src/webenginewidgets/api/qwebenginepage.h
+++ b/src/webenginewidgets/api/qwebenginepage.h
@@ -343,6 +343,7 @@ Q_SIGNALS:
     void recentlyAudibleChanged(bool recentlyAudible);
 
     void pdfPrintingFinished(const QString &filePath, bool success);
+    void printRequested();
 
 protected:
     virtual QWebEnginePage *createWindow(WebWindowType type);
diff --git a/src/webenginewidgets/api/qwebenginepage_p.h b/src/webenginewidgets/api/qwebenginepage_p.h
index e2329e8f8..66a92dec9 100644
--- a/src/webenginewidgets/api/qwebenginepage_p.h
+++ b/src/webenginewidgets/api/qwebenginepage_p.h
@@ -146,6 +146,7 @@ public:
     bool supportsDragging() const override;
     bool isEnabled() const override;
     void setToolTip(const QString &toolTipText) override;
+    void printRequested() override;
     const QObject *holdingQObject() const override;
     ClientType clientType() override { return QtWebEngineCore::WebContentsAdapterClient::WidgetsClient; }