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

chrome/browser/ui/views/panels/taskbar_window_thumbnailer_win.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_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
 #define CHROME_BROWSER_UI_VIEWS_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_
 
 #include <vector>
 #include "base/memory/scoped_ptr.h"
 #include "ui/base/win/hwnd_subclass.h"
 
 class SkBitmap;
 
 class TaskbarWindowThumbnailerDelegateWin {
  public:
   // Returns the list of handles for all windows that are used to construct the
   // thumbnail. If empty list is returned, the snapshot of current window
   // is used.
   virtual std::vector<HWND> GetSnapshotWindowHandles() const = 0;
 };
 
 // Provides the custom thumbnail and live preview for the window that appears
 // in the taskbar (Windows 7 and later).
 class TaskbarWindowThumbnailerWin : public ui::HWNDMessageFilter {
  public:
   TaskbarWindowThumbnailerWin(HWND hwnd,
                               TaskbarWindowThumbnailerDelegateWin* delegate);
-  virtual ~TaskbarWindowThumbnailerWin();
+  ~TaskbarWindowThumbnailerWin() override;
 
   // Starts using the custom snapshot for live preview. The snapshot is only
   // captured once when the system requests it, so the updates of the panels'
   // content will not be automatically reflected in the thumbnail.
   void Start();
 
   // Stops providing the custom snapshot for live preview.
   void Stop();
 
   // Captures the snapshot now instead of when the system requests it.
   void CaptureSnapshot();
 
   // Invalidates the snapshot such that a fresh copy can be obtained next time
   // when the system requests it.
   void InvalidateSnapshot();
 
   // Provide the snapshot to the new window. If the snapshot is captured for the
   // old window, it will also be used for the new window.
   void ReplaceWindow(HWND new_hwnd);
 
  private:
   // Overridden from ui::HWNDMessageFilter:
-  virtual bool FilterMessage(HWND hwnd,
-                             UINT message,
-                             WPARAM w_param,
-                             LPARAM l_param,
-                             LRESULT* l_result) override;
+  bool FilterMessage(HWND hwnd,
+                     UINT message,
+                     WPARAM w_param,
+                     LPARAM l_param,
+                     LRESULT* l_result) override;
 
   // Message handlers.
   bool OnDwmSendIconicThumbnail(int width, int height, LRESULT* l_result);
   bool OnDwmSendIconicLivePreviewBitmap(LRESULT* l_result);
 
   // Captures and returns the screenshot of the window. The caller is
   // responsible to release the returned SkBitmap instance.
   SkBitmap* CaptureWindowImage() const;
 
   HWND hwnd_;
   TaskbarWindowThumbnailerDelegateWin* delegate_;  // Weak, owns us.
   scoped_ptr<SkBitmap> capture_bitmap_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskbarWindowThumbnailerWin);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_PANELS_TASKBAR_WINDOW_THUMBNAILER_WIN_H_