Make printing PDF work from inside PDF extension.

chrome/browser/printing/print_view_manager.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/printing/print_view_manager.h"
 
 #include <map>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/lazy_instance.h"
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/plugins/chrome_plugin_service_filter.h"
 #include "chrome/browser/printing/print_preview_dialog_controller.h"
 #include "chrome/browser/ui/webui/print_preview/print_preview_ui.h"
 #include "chrome/common/chrome_content_client.h"
+#include "components/guest_view/browser/guest_view_base.h"
 #include "components/printing/common/print_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/plugin_service.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/webplugininfo.h"
+#include "extensions/common/constants.h"
 #include "printing/features/features.h"
 
 using content::BrowserThread;
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(printing::PrintViewManager);
 
 namespace {
 
 // Keeps track of pending scripted print preview closures.
 // No locking, only access on the UI thread.
@@ skipping 86 matching lines @@
   DCHECK(!print_preview_rfh_);
   print_preview_rfh_ = rfh;
   print_preview_state_ = USER_INITIATED_PREVIEW;
   return true;
 }
 
 void PrintViewManager::PrintPreviewForWebNode() {
   if (print_preview_state_ != NOT_PREVIEWING)
     return;
   print_preview_state_ = USER_INITIATED_PREVIEW;
+  // If this is a PDF extension loaded inside a MimeHandlerViewGuest then we are
+  // here due to clicking on print button inside the PDF extension. We should
+  // use the main frame of the WebContents for print preview.
+  if (guest_view::GuestViewBase::FromWebContents(web_contents()) &&
+      web_contents()->GetLastCommittedURL().host() ==
+          extension_misc::kPdfExtensionId) {
+    print_preview_rfh_ = web_contents()->GetMainFrame();
+  }
 }
 
 void PrintViewManager::PrintPreviewDone() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   DCHECK_NE(NOT_PREVIEWING, print_preview_state_);
 
   if (print_preview_state_ == SCRIPTED_PREVIEW) {
     auto& map = g_scripted_print_preview_closure_map.Get();
     auto it = map.find(scripted_print_preview_rph_);
     CHECK(it != map.end());
@@ skipping 104 matching lines @@
     IPC_MESSAGE_HANDLER(PrintHostMsg_ShowScriptedPrintPreview,
                         OnShowScriptedPrintPreview)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
 
   return handled ||
          PrintViewManagerBase::OnMessageReceived(message, render_frame_host);
 }
 
 }  // namespace printing