We have a problem in the process on destroying WebContentsImpl because

chrome/browser/extensions/extension_view_host.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_view_host.h"
 
 #include "base/strings/string_piece.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/window_controller.h"
 #include "chrome/browser/file_select_helper.h"
@@ skipping 24 matching lines @@
 // Notifies an ExtensionViewHost when a WebContents is destroyed.
 class ExtensionViewHost::AssociatedWebContentsObserver
     : public WebContentsObserver {
  public:
   AssociatedWebContentsObserver(ExtensionViewHost* host,
                                 WebContents* web_contents)
       : WebContentsObserver(web_contents), host_(host) {}
   virtual ~AssociatedWebContentsObserver() {}
 
   // content::WebContentsObserver:
-  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE {
+  virtual void WebContentsDestroyed() OVERRIDE {
     // Deleting |this| from here is safe.
     host_->SetAssociatedWebContents(NULL);
   }
 
  private:
   ExtensionViewHost* host_;
 
   DISALLOW_COPY_AND_ASSIGN(AssociatedWebContentsObserver);
 };
 
@@ skipping 280 matching lines @@
 
 void ExtensionViewHost::InsertInfobarCSS() {
   static const base::StringPiece css(
       ResourceBundle::GetSharedInstance().GetRawDataResource(
       IDR_EXTENSIONS_INFOBAR_CSS));
 
   host_contents()->InsertCSS(css.as_string());
 }
 
 }  // namespace extensions