Enforce marking "override" for functions overriding Blink.

content/child/webthemeengine_impl_android.h

 // Copyright 2014 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 CONTENT_CHILD_WEBTHEMEENGINE_IMPL_ANDROID_H_
 #define CONTENT_CHILD_WEBTHEMEENGINE_IMPL_ANDROID_H_
 
 #include "third_party/WebKit/public/platform/WebThemeEngine.h"
 
 namespace content {
 
 class WebThemeEngineImpl : public blink::WebThemeEngine {
  public:
   // WebThemeEngine methods:
-  virtual blink::WebSize getSize(blink::WebThemeEngine::Part);
-  virtual void paint(
-      blink::WebCanvas* canvas,
-      blink::WebThemeEngine::Part part,
-      blink::WebThemeEngine::State state,
-      const blink::WebRect& rect,
-      const blink::WebThemeEngine::ExtraParams* extra_params);
+  blink::WebSize getSize(blink::WebThemeEngine::Part) override;
+  void paint(blink::WebCanvas* canvas,
+             blink::WebThemeEngine::Part part,
+             blink::WebThemeEngine::State state,
+             const blink::WebRect& rect,
+             const blink::WebThemeEngine::ExtraParams* extra_params) override;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_WEBTHEMEENGINE_IMPL_ANDROID_H_