We have a problem in the process on destroying WebContentsImpl because

chrome/browser/media_galleries/media_file_system_registry.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/media_galleries/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 67 matching lines @@
   void ReferenceFromRVH(const content::RenderViewHost* rvh);
 
  private:
   class RPHWebContentsObserver : public content::WebContentsObserver {
    public:
     RPHWebContentsObserver(RPHReferenceManager* manager,
                            WebContents* web_contents);
 
    private:
     // content::WebContentsObserver
-    virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+    virtual void WebContentsDestroyed() OVERRIDE;
     virtual void NavigationEntryCommitted(
         const content::LoadCommittedDetails& load_details) OVERRIDE;
 
     RPHReferenceManager* manager_;
   };
 
   class RPHObserver : public content::RenderProcessHostObserver {
    public:
     RPHObserver(RPHReferenceManager* manager, RenderProcessHost* host);
     virtual ~RPHObserver();
@@ skipping 49 matching lines @@
   state->AddWebContentsObserver(contents);
 }
 
 RPHReferenceManager::RPHWebContentsObserver::RPHWebContentsObserver(
     RPHReferenceManager* manager,
     WebContents* web_contents)
     : content::WebContentsObserver(web_contents),
       manager_(manager) {
 }
 
-void RPHReferenceManager::RPHWebContentsObserver::WebContentsDestroyed(
-    WebContents* web_contents) {
-  manager_->OnWebContentsDestroyedOrNavigated(web_contents);
+void RPHReferenceManager::RPHWebContentsObserver::WebContentsDestroyed() {
+  manager_->OnWebContentsDestroyedOrNavigated(web_contents());
 }
 
 void RPHReferenceManager::RPHWebContentsObserver::NavigationEntryCommitted(
     const content::LoadCommittedDetails& load_details) {
   if (load_details.is_in_page)
     return;
 
   manager_->OnWebContentsDestroyedOrNavigated(web_contents());
 }
 
@@ skipping 656 matching lines @@
   DCHECK_EQ(1U, erase_count);
   if (extension_hosts->second.empty()) {
     // When a profile has no ExtensionGalleriesHosts left, remove the
     // matching gallery-change-watcher since it is no longer needed. Leave the
     // |extension_hosts| entry alone, since it indicates the profile has been
     // previously used.
     MediaGalleriesPreferences* preferences = GetPreferences(profile);
     preferences->RemoveGalleryChangeObserver(this);
   }
 }