Have LazyBackgroundTaskQueue notify consumers when the transient page fails to

chrome/browser/extensions/extension_event_router.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_event_router.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/api/runtime/runtime_api.h"
@@ skipping 405 matching lines @@
   const Extension* extension = profile->GetExtensionService()->extensions()->
       GetByID(extension_id);
   if (extension && extension->has_lazy_background_page()) {
     profile->GetExtensionProcessManager()->DecrementLazyKeepaliveCount(
         extension);
   }
 }
 
 void ExtensionEventRouter::DispatchPendingEvent(
     const linked_ptr<ExtensionEvent>& event, ExtensionHost* host) {
+  if (!host)
+    return;
+
   ListenerProcess listener(host->render_process_host(),
                            host->extension()->id());
   if (listeners_[event->event_name].count(listener) > 0u)
     DispatchEventToListener(listener, event);
 }
 
 void ExtensionEventRouter::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
@@ skipping 50 matching lines @@
           content::Details<const Extension>(details).ptr();
       extensions::RuntimeEventRouter::DispatchOnInstalledEvent(
           profile_, extension);
       break;
     }
     default:
       NOTREACHED();
       return;
   }
 }