Cancel prerender when we discover a download starting from a page we are prer...

chrome/browser/prerender/prerender_contents.cc

 // Copyright (c) 2011 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/prerender/prerender_contents.h"
 
 #include "base/metrics/histogram.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/background_contents_service.h"
 #include "chrome/browser/browsing_instance.h"
 #include "chrome/browser/prerender/prerender_manager.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
+#include "chrome/browser/renderer_host/resource_request_details.h"
 #include "chrome/browser/renderer_host/site_instance.h"
 #include "chrome/browser/renderer_preferences_util.h"
 #include "chrome/browser/ui/login/login_prompt.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/notification_service.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/common/view_types.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/render_messages_params.h"
 #include "ui/gfx/rect.h"
@@ skipping 51 matching lines @@
                  Source<Profile>(profile_));
   render_view_host_->CreateRenderView(string16());
 
   // Register to cancel if Authentication is required.
   registrar_.Add(this, NotificationType::AUTH_NEEDED,
                  NotificationService::AllSources());
 
   registrar_.Add(this, NotificationType::AUTH_CANCELLED,
                  NotificationService::AllSources());
 
+  // Register all responses to see if we should cancel.
+  registrar_.Add(this, NotificationType::DOWNLOAD_INITIATED,
+                 Source<RenderViewHostDelegate>(this));
+
   DCHECK(load_start_time_.is_null());
   load_start_time_ = base::TimeTicks::Now();
 
   ViewMsg_Navigate_Params params;
   params.url = prerender_url_;
   params.transition = PageTransition::LINK;
   params.navigation_type = ViewMsg_Navigate_Params::PRERENDER;
   render_view_host_->Navigate(params);
 }
 
 void PrerenderContents::set_final_status(FinalStatus final_status) {
   DCHECK(final_status >= FINAL_STATUS_USED && final_status < FINAL_STATUS_MAX);
   DCHECK_EQ(FINAL_STATUS_MAX, final_status_);
+
   final_status_ = final_status;
 }
 
 PrerenderContents::FinalStatus PrerenderContents::final_status() const {
   return final_status_;
 }
 
 PrerenderContents::~PrerenderContents() {
   DCHECK(final_status_ != FINAL_STATUS_MAX);
   UMA_HISTOGRAM_ENUMERATION("Prerender.FinalStatus",
@@ skipping 71 matching lines @@
   return false;
 }
 
 void PrerenderContents::Observe(NotificationType type,
                                 const NotificationSource& source,
                                 const NotificationDetails& details) {
   switch (type.value) {
     case NotificationType::PROFILE_DESTROYED:
       Destroy(FINAL_STATUS_PROFILE_DESTROYED);
       return;
+
     case NotificationType::APP_TERMINATING:
       Destroy(FINAL_STATUS_APP_TERMINATING);
       return;
 
     case NotificationType::AUTH_NEEDED:
     case NotificationType::AUTH_CANCELLED: {
       // Prerendered pages have a NULL controller and the login handler should
       // be referencing us as the render view host delegate.
       NavigationController* controller =
           Source<NavigationController>(source).ptr();
       LoginNotificationDetails* details_ptr =
           Details<LoginNotificationDetails>(details).ptr();
       LoginHandler* handler = details_ptr->handler();
       DCHECK(handler != NULL);
       RenderViewHostDelegate* delegate = handler->GetRenderViewHostDelegate();
-      if (controller == NULL && delegate == this)
+      if (controller == NULL && delegate == this) {
         Destroy(FINAL_STATUS_AUTH_NEEDED);
+        return;
+      }
       break;
     }
 
+    case NotificationType::DOWNLOAD_INITIATED: {
+      // If the download is started from a RenderViewHost that we are
+      // delegating, kill the prerender. This will also stop the download and

[Randy Smith (Not in Mondays), 2011/02/10 16:57:10]

Can you give me the context for how killing the prerender stops the download?  I
thought that the download never got started because the limiter blocked it.

[dominich, 2011/02/10 18:46:22]

You're right - changed the comment to reflect that.

When the prerender is cancelled, the RenderViewHost is shutdown and deleted and
unless I've missed something this cancels all requests made from that
RenderViewHost.

Done.

+      // navigating to the page will restart it as expected.
+      DCHECK(Source<RenderViewHostDelegate>(source).ptr() == this);
+      Destroy(FINAL_STATUS_DOWNLOAD);
+      return;
+    }
+
     default:
       NOTREACHED() << "Unexpected notification sent.";
       break;
   }
 }
 
 void PrerenderContents::OnMessageBoxClosed(IPC::Message* reply_msg,
                                            bool success,
                                            const std::wstring& prompt) {
   render_view_host_->JavaScriptMessageBoxClosed(reply_msg, success, prompt);
@@ skipping 121 matching lines @@
 
 void PrerenderContents::DidStopLoading() {
   has_stopped_loading_ = true;
 }
 
 void PrerenderContents::Destroy(FinalStatus final_status) {
   prerender_manager_->RemoveEntry(this);
   set_final_status(final_status);
   delete this;
 }