We have a problem in the process on destroying WebContentsImpl because

content/browser/media/capture/web_contents_tracker.h

 // 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.
 //
 // Given a starting render_process_id and render_view_id, the WebContentsTracker
 // tracks RenderViewHost instance swapping during the lifetime of a WebContents
 // instance.  This is used when mirroring tab video and audio so that user
 // navigations, crashes, etc., during a tab's lifetime allow the capturing code
 // to remain active on the current/latest RenderView.
 //
@@ skipping 55 matching lines @@
   // |render_process_id| and |render_view_id| and begin observing it.
   void LookUpAndObserveWebContents(int render_process_id,
                                    int render_view_id);
 
   // WebContentsObserver overrides to react to events of interest.
   virtual void RenderViewReady() OVERRIDE;
   virtual void AboutToNavigateRenderView(RenderViewHost* render_view_host)
       OVERRIDE;
   virtual void DidNavigateMainFrame(const LoadCommittedDetails& details,
                                     const FrameNavigateParams& params) OVERRIDE;
-  virtual void WebContentsDestroyed(WebContents* web_contents) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
   ChangeCallback callback_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsTracker);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEDIA_CAPTURE_WEB_CONTENTS_TRACKER_H_