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

content/shell/renderer/test_runner/web_frame_test_proxy.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_SHELL_RENDERER_TEST_RUNNER_WEB_FRAME_TEST_PROXY_H_
 #define CONTENT_SHELL_RENDERER_TEST_RUNNER_WEB_FRAME_TEST_PROXY_H_
 
 #include "base/basictypes.h"
 #include "content/shell/renderer/test_runner/mock_screen_orientation_client.h"
 #include "content/shell/renderer/test_runner/test_interfaces.h"
@@ skipping 267 matching lines @@
         source_frame, target_frame, target, event);
   }
 
   virtual void didStopLoading() {
     base_proxy_->DidStopLoading();
     Base::didStopLoading();
   }
 
  private:
 #if defined(ENABLE_WEBRTC)
-  virtual scoped_ptr<MediaStreamRendererFactory> CreateRendererFactory()
-      override {
+  scoped_ptr<MediaStreamRendererFactory> CreateRendererFactory() override {
     return scoped_ptr<MediaStreamRendererFactory>(
         new TestMediaStreamRendererFactory());
   }
 #endif
 
   WebTestProxyBase* base_proxy_;
 
   DISALLOW_COPY_AND_ASSIGN(WebFrameTestProxy);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_SHELL_RENDERER_TEST_RUNNER_WEB_FRAME_TEST_PROXY_H_