Componentize sad_tab

chrome/browser/ui/sad_tab_helper.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 CHROME_BROWSER_UI_SAD_TAB_HELPER_H_
-#define CHROME_BROWSER_UI_SAD_TAB_HELPER_H_
-
-#include "base/basictypes.h"
-#include "base/compiler_specific.h"
-#include "base/memory/scoped_ptr.h"
-#include "content/public/browser/web_contents_observer.h"
-#include "content/public/browser/web_contents_user_data.h"
-
-namespace chrome {
-class SadTab;
-}
-
-// Per-tab class to manage sad tab views.
-class SadTabHelper : public content::WebContentsObserver,
-                     public content::WebContentsUserData<SadTabHelper> {
- public:
-  virtual ~SadTabHelper();
-
-  chrome::SadTab* sad_tab() { return sad_tab_.get(); }
-
- private:
-  friend class content::WebContentsUserData<SadTabHelper>;
-
-  explicit SadTabHelper(content::WebContents* web_contents);
-
-  void InstallSadTab(base::TerminationStatus status);
-
-  // Overridden from content::WebContentsObserver:
-  virtual void RenderViewReady() OVERRIDE;
-  virtual void RenderProcessGone(base::TerminationStatus status) OVERRIDE;
-
-  scoped_ptr<chrome::SadTab> sad_tab_;
-
-  DISALLOW_COPY_AND_ASSIGN(SadTabHelper);
-};
-
-#endif  // CHROME_BROWSER_UI_SAD_TAB_HELPER_H_