We have a problem in the process on destroying WebContentsImpl because

ui/keyboard/keyboard_controller_proxy.cc

 // Copyright (c) 2013 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 "ui/keyboard/keyboard_controller_proxy.h"
 
 #include "base/command_line.h"
 #include "base/values.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
@@ skipping 50 matching lines @@
   }
 
   // Overridden from content::WebContentsDelegate:
   virtual void RequestMediaAccessPermission(content::WebContents* web_contents,
       const content::MediaStreamRequest& request,
       const content::MediaResponseCallback& callback) OVERRIDE {
     proxy_->RequestAudioInput(web_contents, request, callback);
   }
 
   // Overridden from content::WebContentsObserver:
-  virtual void WebContentsDestroyed(content::WebContents* contents) OVERRIDE {
+  virtual void WebContentsDestroyed() OVERRIDE {
     delete this;
   }
 
   keyboard::KeyboardControllerProxy* proxy_;
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardContentsDelegate);
 };
 
 }  // namespace
 
@@ skipping 75 matching lines @@
   DCHECK(keyboard_contents_);
   if (keyboard_contents_->GetURL() != GetVirtualKeyboardUrl()) {
     LoadContents(GetVirtualKeyboardUrl());
   }
 }
 
 void KeyboardControllerProxy::SetupWebContents(content::WebContents* contents) {
 }
 
 }  // namespace keyboard