Improve syncing between dom distiller and the print preview request

chrome/browser/ui/webui/print_preview/print_preview_distiller.cc

 // 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.
 
 #include "chrome/browser/ui/webui/print_preview/print_preview_distiller.h"
 
 #include <stdint.h>
 #include <string>
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/feature_list.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/dom_distiller/tab_utils.h"
 #include "chrome/browser/printing/print_preview_dialog_controller.h"
 #include "chrome/browser/printing/print_preview_message_handler.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/web_contents_sizer.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/prerender_messages.h"
 #include "components/dom_distiller/content/browser/distiller_javascript_utils.h"
 #include "components/printing/common/print_messages.h"
+#include "content/public/browser/navigation_details.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/resource_request_details.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "content/public/browser/web_contents_observer.h"
@@ skipping 94 matching lines @@
       content::RenderFrameHost* render_frame_host) override {
     // When a new RenderFrame is created for a distilled rendering
     // WebContents, tell the new RenderFrame it's being used for
     // prerendering before any navigations occur.  Note that this is
     // always triggered before the first navigation, so there's no
     // need to send the message just after the WebContents is created.
     render_frame_host->Send(new PrerenderMsg_SetIsPrerendering(
         render_frame_host->GetRoutingID(), true));
   }
 
-  void DidFinishLoad(content::RenderFrameHost* render_frame_host,
-                     const GURL& validated_url) override {
-    // Ask the page to trigger an anchor navigation once the distilled
-    // contents are added to the page.
-    dom_distiller::RunIsolatedJavaScript(
-        web_contents()->GetMainFrame(),
-        "navigate_on_initial_content_load = true;");
-  }
-
-  void DidNavigateMainFrame(
-      const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) override {
-    // The second content loads signals that the distilled contents have
-    // been delivered to the page via inline JavaScript execution.
-    if (web_contents()->GetController().GetEntryCount() > 1) {
-      RenderViewHost* rvh = web_contents()->GetRenderViewHost();
-      rvh->Send(new PrintMsg_InitiatePrintPreview(rvh->GetRoutingID(), false));
-      rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings_));
-    }
+  void DoPrintPreview() {
+    RenderViewHost* rvh = web_contents()->GetRenderViewHost();
+    rvh->Send(new PrintMsg_InitiatePrintPreview(rvh->GetRoutingID(), false));
+    rvh->Send(new PrintMsg_PrintPreview(rvh->GetRoutingID(), *settings_));
   }
 
   void DidGetRedirectForResourceRequest(
       content::RenderFrameHost* render_frame_host,
       const content::ResourceRedirectDetails& details) override {
     if (details.resource_type != content::RESOURCE_TYPE_MAIN_FRAME)
       return;
     // Redirects are unsupported for distilled content renderers.
     on_failed_callback_.Run();
   }
 
   void RenderProcessGone(base::TerminationStatus status) override {
     on_failed_callback_.Run();
   }
 
+  void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) override {
+    // Wait until we are done distilling the article and the target
+    // WebContents is ready for printing.
+    // The navigation to notify print preview that content is on the page will
+    // be an in-page navigation.
+    if (!details.is_in_page)
+      return;
+    // TODO(mvendra, wychen): resources (images, web fonts) are not necessarily
+    //                        ready at this point - so deferring the call to
+    //                        DoPrintPreview could be warranted
+    DoPrintPreview();
+  }
+
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override {
     switch (type) {
       // TODO(davidben): Try to remove this in favor of relying on
       // FINAL_STATUS_PROFILE_DESTROYED.
       case chrome::NOTIFICATION_APP_TERMINATING:
         on_failed_callback_.Run();
         return;
 
@@ skipping 93 matching lines @@
     WebContents* source_web_contents) {
   // TODO(ajwong): Remove the temporary map once prerendering is aware of
   // multiple session storage namespaces per tab.
   content::SessionStorageNamespaceMap session_storage_namespace_map;
   Profile* profile =
       Profile::FromBrowserContext(source_web_contents->GetBrowserContext());
   session_storage_namespace_map[std::string()] = session_storage_namespace;
   return WebContents::CreateWithSessionStorage(
       WebContents::CreateParams(profile), session_storage_namespace_map);
 }