We have a problem in the process on destroying WebContentsImpl because

content/browser/android/web_contents_observer_android.h

 // 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.
 
 #ifndef CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_ANDROID_H_
 #define CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_ANDROID_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
@@ skipping 58 matching lines @@
       bool is_main_frame,
       const GURL& url,
       PageTransition transition_type,
       RenderViewHost* render_view_host) OVERRIDE;
   virtual void DidFinishLoad(int64 frame_id,
                              const GURL& validated_url,
                              bool is_main_frame,
                              RenderViewHost* render_view_host) OVERRIDE;
   virtual void NavigationEntryCommitted(
       const LoadCommittedDetails& load_details) OVERRIDE;
-  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
   virtual void DidChangeVisibleSSLState() OVERRIDE;
   virtual void DidAttachInterstitialPage() OVERRIDE;
   virtual void DidDetachInterstitialPage() OVERRIDE;
 
   void DidFailLoadInternal(bool is_provisional_load,
                            bool is_main_frame,
                            int error_code,
                            const base::string16& description,
                            const GURL& url);
 
   JavaObjectWeakGlobalRef weak_java_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserverAndroid);
 };
 
 bool RegisterWebContentsObserverAndroid(JNIEnv* env);
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_WEB_CONTENTS_OBSERVER_ANDROID_H_