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

chrome/test/data/webui/async_gen.h

 // Copyright (c) 2011 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_TEST_DATA_WEBUI_ASYNC_GEN_H_
 #define CHROME_TEST_DATA_WEBUI_ASYNC_GEN_H_
 
 #include "chrome/test/base/web_ui_browser_test.h"
 #include "content/public/browser/web_ui_message_handler.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace base {
 class ListValue;
 }  // namespace base
 
 // C++ support class for javascript-generated asynchronous tests.
 class WebUIBrowserAsyncGenTest : public WebUIBrowserTest {
  public:
   WebUIBrowserAsyncGenTest();
-  virtual ~WebUIBrowserAsyncGenTest();
+  ~WebUIBrowserAsyncGenTest() override;
 
  protected:
   class AsyncWebUIMessageHandler : public content::WebUIMessageHandler {
    public:
     AsyncWebUIMessageHandler();
     ~AsyncWebUIMessageHandler();
 
     MOCK_METHOD1(HandleTearDown, void(const base::ListValue*));
 
    private:
     void HandleCallJS(const base::ListValue* list_value);
 
     // WebUIMessageHandler implementation.
-    virtual void RegisterMessages() override;
+    void RegisterMessages() override;
   };
 
   // Handler for this test fixture.
   ::testing::StrictMock<AsyncWebUIMessageHandler> message_handler_;
 
  private:
   // Provide this object's handler.
-  virtual content::WebUIMessageHandler* GetMockMessageHandler() override {
+  content::WebUIMessageHandler* GetMockMessageHandler() override {
     return &message_handler_;
   }
 
-  virtual void SetUpOnMainThread() override {
+  void SetUpOnMainThread() override {
     WebUIBrowserTest::SetUpOnMainThread();
     EXPECT_CALL(message_handler_, HandleTearDown(::testing::_));
   }
 
   DISALLOW_COPY_AND_ASSIGN(WebUIBrowserAsyncGenTest);
 };
 
 #endif  // CHROME_TEST_DATA_WEBUI_ASYNC_GEN_H_