Don't report blocked web contents from already navigated render views.

chrome/browser/chrome_content_browser_client.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/chrome_content_browser_client.h"
 
 #include <set>
 #include <utility>
 #include <vector>
 
@@ skipping 497 matching lines @@
   return effective_url;
 }
 #endif
 
 void SetApplicationLocaleOnIOThread(const std::string& locale) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   g_io_thread_application_locale.Get() = locale;
 }
 
 void HandleBlockedPopupOnUIThread(const BlockedWindowParams& params) {
-  WebContents* tab = tab_util::GetWebContentsByID(params.render_process_id(),
-                                                  params.opener_id());
-  if (!tab)
+  // TODO(jochen): This code path should use RenderFrameHosts. See
+  // http://crbug.com/431769 for details.
+  RenderViewHost* render_view_host =
+      RenderViewHost::FromID(params.render_process_id(), params.opener_id());
+  if (!render_view_host)
+    return;
+  WebContents* tab = WebContents::FromRenderViewHost(render_view_host);
+  // The tab might already have navigated away.
+  if (!tab || tab->GetRenderViewHost() != render_view_host)
     return;
 
   prerender::PrerenderContents* prerender_contents =
       prerender::PrerenderContents::FromWebContents(tab);
   if (prerender_contents) {
     prerender_contents->Destroy(prerender::FINAL_STATUS_CREATE_NEW_WINDOW);
     return;
   }
 
   PopupBlockerTabHelper* popup_helper =
@@ skipping 2146 matching lines @@
       switches::kDisableWebRtcEncryption,
     };
     to_command_line->CopySwitchesFrom(from_command_line,
                                       kWebRtcDevSwitchNames,
                                       arraysize(kWebRtcDevSwitchNames));
   }
 }
 #endif  // defined(ENABLE_WEBRTC)
 
 }  // namespace chrome