Always use opaque frame for extension app windows

chrome/browser/views/frame/opaque_browser_frame_view.h

 // Copyright (c) 2010 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_VIEWS_FRAME_OPAQUE_BROWSER_FRAME_VIEW_H_
 #define CHROME_BROWSER_VIEWS_FRAME_OPAQUE_BROWSER_FRAME_VIEW_H_
 
 #include "chrome/browser/views/frame/browser_frame.h"
 #include "chrome/browser/views/frame/browser_non_client_frame_view.h"
 #include "chrome/browser/views/tab_icon_view.h"
@@ skipping 22 matching lines @@
   // Overridden from BrowserNonClientFrameView:
   virtual gfx::Rect GetBoundsForTabStrip(BaseTabStrip* tabstrip) const;
   virtual void UpdateThrobber(bool running);
   virtual gfx::Size GetMinimumSize();
   virtual void PaintTabStripShadow(gfx::Canvas* canvas);
 
  protected:
   // Overridden from views::NonClientFrameView:
   virtual gfx::Rect GetBoundsForClientView() const;
   virtual bool AlwaysUseNativeFrame() const;
+  virtual bool AlwaysUseCustomFrame() const;
   virtual gfx::Rect GetWindowBoundsForClientBounds(
       const gfx::Rect& client_bounds) const;
   virtual int NonClientHitTest(const gfx::Point& point);
   virtual void GetWindowMask(const gfx::Size& size, gfx::Path* window_mask);
   virtual void EnableClose(bool enable);
   virtual void ResetWindowControls();
 
   // Overridden from views::View:
   virtual void Paint(gfx::Canvas* canvas);
   virtual void Layout();
@@ skipping 77 matching lines @@
   // The BrowserView hosted within this View.
   BrowserView* browser_view_;
 
   // The bounds of the ClientView.
   gfx::Rect client_view_bounds_;
 
   DISALLOW_EVIL_CONSTRUCTORS(OpaqueBrowserFrameView);
 };
 
 #endif  // CHROME_BROWSER_VIEWS_FRAME_OPAQUE_BROWSER_FRAME_VIEW_H_