Make a clean interface for dialog callbacks.

content/browser/tab_contents/tab_contents.h

 // Copyright (c) 2011 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_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 #define CONTENT_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 426 matching lines @@
   void set_closed_by_user_gesture(bool value) {
     closed_by_user_gesture_ = value;
   }
   bool closed_by_user_gesture() const { return closed_by_user_gesture_; }
 
   // Overridden from JavaScriptDialogDelegate:
   virtual void OnDialogClosed(IPC::Message* reply_msg,
                               bool success,
                               const string16& user_input) OVERRIDE;
   virtual gfx::NativeWindow GetDialogRootWindow() OVERRIDE;
-  virtual TabContents* AsTabContents() OVERRIDE;
-  virtual ExtensionHost* AsExtensionHost() OVERRIDE;
+  virtual void OnDialogShown() OVERRIDE;
 
   // The BookmarkDragDelegate is used to forward bookmark drag and drop events
   // to extensions.
   virtual RenderViewHostDelegate::BookmarkDrag* GetBookmarkDragDelegate();
 
   // It is up to callers to call SetBookmarkDragDelegate(NULL) when
   // |bookmark_drag| is deleted since this class does not take ownership of
   // |bookmark_drag|.
   virtual void SetBookmarkDragDelegate(
       RenderViewHostDelegate::BookmarkDrag* bookmark_drag);
@@ skipping 391 matching lines @@
   ObserverList<TabContentsObserver> observers_;
 
   // Content restrictions, used to disable print/copy etc based on content's
   // (full-page plugins for now only) permissions.
   int content_restrictions_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContents);
 };
 
 #endif  // CONTENT_BROWSER_TAB_CONTENTS_TAB_CONTENTS_H_