Fix bug where transient pages would miss events dispatched while it was

chrome/browser/extensions/extension_function.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/extensions/extension_function.h"
 
 #include "base/json/json_writer.h"
 #include "base/logging.h"
 #include "chrome/browser/extensions/extension_function_dispatcher.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 134 matching lines @@
     if (process)
       base::KillProcess(process, content::RESULT_CODE_KILLED_BAD_MESSAGE,
                         false);
   }
 }
 UIThreadExtensionFunction::UIThreadExtensionFunction()
     : render_view_host_(NULL), profile_(NULL), delegate_(NULL) {
 }
 
 UIThreadExtensionFunction::~UIThreadExtensionFunction() {
-  if (dispatcher())
+  if (dispatcher() && render_view_host())
     dispatcher()->OnExtensionFunctionCompleted(GetExtension());
 }
 
 UIThreadExtensionFunction*
 UIThreadExtensionFunction::AsUIThreadExtensionFunction() {
   return this;
 }
 
 bool UIThreadExtensionFunction::OnMessageReceivedFromRenderView(
     const IPC::Message& message) {
@@ skipping 71 matching lines @@
 
 SyncIOThreadExtensionFunction::SyncIOThreadExtensionFunction() {
 }
 
 SyncIOThreadExtensionFunction::~SyncIOThreadExtensionFunction() {
 }
 
 void SyncIOThreadExtensionFunction::Run() {
   SendResponse(RunImpl());
 }