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

android_webview/native/aw_message_port_service_impl.h

 // Copyright 2015 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 ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_
 #define ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_
 
 #include <jni.h>
 #include <map>
 
 #include "android_webview/browser/aw_message_port_service.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 
 namespace android_webview {
 
 // This class is the native peer of AwMessagePortService.java. Please see the
 // java class for an explanation of use, ownership and lifetime.
 
 // Threading: Created and initialized on UI thread. For other methods, see
 // the method level DCHECKS or documentation.
 class AwMessagePortServiceImpl : public AwMessagePortService {
  public:
   static AwMessagePortServiceImpl* GetInstance();
 
   AwMessagePortServiceImpl();
-  ~AwMessagePortServiceImpl();
+  ~AwMessagePortServiceImpl() override;
   void Init(JNIEnv* env, jobject object);
 
   void CreateMessageChannel(JNIEnv* env, jobject callback,
       scoped_refptr<AwMessagePortMessageFilter> filter);
 
   // AwMessagePortService implementation
   void OnConvertedWebToAppMessage(
       int message_port_id,
       const base::ListValue& message,
       const std::vector<int>& sent_message_port_ids) override;
@@ skipping 26 matching lines @@
   MessagePorts ports_; // Access on IO thread
 
   DISALLOW_COPY_AND_ASSIGN(AwMessagePortServiceImpl);
 };
 
 bool RegisterAwMessagePortService(JNIEnv* env);
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_NATIVE_AW_MESSAGE_PORT_SERVICE_IMPL_H_