Show "About panel" bubble on Windows.

chrome/browser/ui/browser_window.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 CHROME_BROWSER_UI_BROWSER_WINDOW_H_
 #define CHROME_BROWSER_UI_BROWSER_WINDOW_H_
 #pragma once
 
 #include "chrome/common/content_settings_types.h"
 #include "content/browser/tab_contents/navigation_entry.h"
@@ skipping 321 matching lines @@
 
   // Return the correct disposition for a popup window based on |bounds|.
   virtual WindowOpenDisposition GetDispositionForPopupBounds(
       const gfx::Rect& bounds) = 0;
 
 #if defined(OS_CHROMEOS)
   // Shows the keyboard overlay dialog box.
   virtual void ShowKeyboardOverlay(gfx::NativeWindow owning_window) = 0;
 #endif
 
+  // Returns a pointer to the Panel instance if the browser window is indeed a
+  // panel, or NULL if there is none.
+  virtual Panel* GetAsPanel() { return NULL; }
+
   // Construct a BrowserWindow implementation for the specified |browser|.
   static BrowserWindow* CreateBrowserWindow(Browser* browser);
 
   // Construct a FindBar implementation for the specified |browser|.
   static FindBar* CreateFindBar(Browser* browser_window);
 
  protected:
   friend class BrowserList;
   friend class BrowserView;
   virtual void DestroyBrowser() = 0;
@@ skipping 27 matching lines @@
 
   // Returns the ToolbarView.
   virtual ToolbarView* GetToolbarView() const = 0;
 #endif
 
  protected:
   virtual ~BrowserWindowTesting() {}
 };
 
 #endif  // CHROME_BROWSER_UI_BROWSER_WINDOW_H_