We have a problem in the process on destroying WebContentsImpl because

chrome/browser/extensions/active_tab_permission_granter.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/active_tab_permission_granter.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 65 matching lines @@
 
 void ActiveTabPermissionGranter::DidNavigateMainFrame(
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
   if (details.is_in_page)
     return;
   DCHECK(details.is_main_frame);  // important: sub-frames don't get granted!
   ClearActiveExtensionsAndNotify();
 }
 
-void ActiveTabPermissionGranter::WebContentsDestroyed(
-    content::WebContents* web_contents) {
+void ActiveTabPermissionGranter::WebContentsDestroyed() {
   ClearActiveExtensionsAndNotify();
 }
 
 void ActiveTabPermissionGranter::OnExtensionUnloaded(
     content::BrowserContext* browser_context,
     const Extension* extension,
     UnloadedExtensionInfo::Reason reason) {
   // Note: don't need to clear the permissions (nor tell the renderer about it)
   // because it's being unloaded anyway.
   granted_extensions_.Remove(extension->id());
 }
 
 void ActiveTabPermissionGranter::ClearActiveExtensionsAndNotify() {
   if (granted_extensions_.is_empty())
     return;
 
   std::vector<std::string> extension_ids;
 
   for (ExtensionSet::const_iterator it = granted_extensions_.begin();
        it != granted_extensions_.end(); ++it) {
     PermissionsData::ClearTabSpecificPermissions(it->get(), tab_id_);
     extension_ids.push_back((*it)->id());
   }
 
   Send(new ExtensionMsg_ClearTabSpecificPermissions(tab_id_, extension_ids));
   granted_extensions_.Clear();
 }
 
 }  // namespace extensions