chrome: Cleanup class/struct forward declarations

chrome/browser/ui/views/frame/native_browser_frame.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_VIEWS_FRAME_NATIVE_BROWSER_FRAME_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_NATIVE_BROWSER_FRAME_H_
 
 #include "ui/base/ui_base_types.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/views/widget/widget.h"
 
 class BrowserFrame;
-class BrowserView;
 
 namespace content {
 struct NativeWebKeyboardEvent;
 }
 
-namespace views {
-class NativeWidget;
-}
-
 class NativeBrowserFrame {
  public:
   virtual ~NativeBrowserFrame() {}
 
   // Returns the platform specific InitParams for initializing our widget.
   virtual views::Widget::InitParams GetWidgetParams() = 0;
 
   // Returns |true| if we should use the custom frame.
   virtual bool UseCustomFrame() const = 0;
 
@@ skipping 18 matching lines @@
 
  protected:
   friend class BrowserFrame;
 
   // BrowserFrame pass-thrus ---------------------------------------------------
   // See browser_frame.h for documentation:
   virtual int GetMinimizeButtonOffset() const = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_NATIVE_BROWSER_FRAME_H_