Fix linux_aura clang build.

chrome/browser/ui/views/frame/desktop_browser_frame_aura.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_DESKTOP_BROWSER_FRAME_AURA_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_DESKTOP_BROWSER_FRAME_AURA_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/views/frame/native_browser_frame.h"
@@ skipping 22 matching lines @@
  public:
   DesktopBrowserFrameAura(BrowserFrame* browser_frame,
                           BrowserView* browser_view);
 
   BrowserView* browser_view() const { return browser_view_; }
 
  protected:
   // Overridden from views::DesktopNativeWidgetAura:
   virtual void InitNativeWidget(
       const views::Widget::InitParams& params) OVERRIDE;
-  void OnWindowDestroying() OVERRIDE;
+  virtual void OnWindowDestroying() OVERRIDE;
 
   // Overridden from NativeBrowserFrame:
   virtual views::NativeWidget* AsNativeWidget() OVERRIDE;
   virtual const views::NativeWidget* AsNativeWidget() const OVERRIDE;
   virtual void InitSystemContextMenu() OVERRIDE;
   virtual int GetMinimizeButtonOffset() const OVERRIDE;
   virtual void TabStripDisplayModeChanged() OVERRIDE;
 
  private:
   virtual ~DesktopBrowserFrameAura();
 
   // The BrowserView is our ClientView. This is a pointer to it.
   BrowserView* browser_view_;
   BrowserFrame* browser_frame_;
 
   // Owned by the RootWindow.
   BrowserDesktopRootWindowHost* browser_desktop_root_window_host_;
 
   // System menu.
   scoped_ptr<views::MenuRunner> menu_runner_;
 
   scoped_ptr<views::corewm::VisibilityController> visibility_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopBrowserFrameAura);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_DESKTOP_BROWSER_FRAME_AURA_H_