We have a problem in the process on destroying WebContentsImpl because

content/shell/browser/shell_devtools_frontend.h

 // Copyright 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.
 
 #ifndef CONTENT_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_
 #define CONTENT_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
@@ skipping 26 matching lines @@
 
   Shell* frontend_shell() const { return frontend_shell_; }
 
  private:
   ShellDevToolsFrontend(Shell* frontend_shell, DevToolsAgentHost* agent_host);
   virtual ~ShellDevToolsFrontend();
 
   // WebContentsObserver overrides
   virtual void RenderViewCreated(RenderViewHost* render_view_host) OVERRIDE;
   virtual void DocumentOnLoadCompletedInMainFrame(int32 page_id) OVERRIDE;
-  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
 
   // DevToolsFrontendHostDelegate implementation
   virtual void DispatchOnEmbedder(const std::string& message) OVERRIDE {}
 
   virtual void InspectedContentsClosing() OVERRIDE;
 
   Shell* frontend_shell_;
   scoped_refptr<DevToolsAgentHost> agent_host_;
   scoped_ptr<DevToolsClientHost> frontend_host_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDevToolsFrontend);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_BROWSER_SHELL_DEVTOOLS_FRONTEND_H_