Update {virtual,override} to follow C++11 style in chrome.

chrome/browser/ui/views/tabs/tab_strip.cc

 // 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.
 
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 
 #if defined(OS_WIN)
 #include <windowsx.h>
 #endif
 
@@ skipping 238 matching lines @@
 
   // Set the background offset used to match the background image to the frame
   // image.
   void set_background_offset(const gfx::Point& offset) {
     background_offset_ = offset;
   }
 
  protected:
   // views::View:
 #if defined(OS_WIN)
-  virtual void OnMouseReleased(const ui::MouseEvent& event) override;
+  void OnMouseReleased(const ui::MouseEvent& event) override;
 #endif
   void OnPaint(gfx::Canvas* canvas) override;
 
   // ui::EventHandler:
   void OnGestureEvent(ui::GestureEvent* event) override;
 
  private:
   // views::MaskedTargeterDelegate:
   bool GetHitTestMask(gfx::Path* mask) const override;
 
@@ skipping 2495 matching lines @@
           ConvertPointToViewAndGetEventHandler(this, newtab_button_, point);
       if (view)
         return view;
     }
     Tab* tab = FindTabForEvent(point);
     if (tab)
       return ConvertPointToViewAndGetEventHandler(this, tab, point);
   }
   return this;
 }