Standardize usage of virtual/override/final in components/

components/invalidation/gcm_invalidation_bridge.cc

Index: components/invalidation/gcm_invalidation_bridge.cc
diff --git a/components/invalidation/gcm_invalidation_bridge.cc b/components/invalidation/gcm_invalidation_bridge.cc
index 1ff5aa6dc4ac99c2158463b08453144418b3027b..23cb09e1141ef165cd43c778ecb42757da840cf8 100644
--- a/components/invalidation/gcm_invalidation_bridge.cc
+++ b/components/invalidation/gcm_invalidation_bridge.cc
@@ -38,14 +38,14 @@ class GCMInvalidationBridge::Core : public syncer::GCMNetworkChannelDelegate,
  public:
   Core(base::WeakPtr<GCMInvalidationBridge> bridge,
        scoped_refptr<base::SingleThreadTaskRunner> ui_thread_task_runner);
-  virtual ~Core();
+  ~Core() override;
 
   // syncer::GCMNetworkChannelDelegate implementation.
-  virtual void Initialize(ConnectionStateCallback callback) override;
-  virtual void RequestToken(RequestTokenCallback callback) override;
-  virtual void InvalidateToken(const std::string& token) override;
-  virtual void Register(RegisterCallback callback) override;
-  virtual void SetMessageReceiver(MessageCallback callback) override;
+  void Initialize(ConnectionStateCallback callback) override;
+  void RequestToken(RequestTokenCallback callback) override;
+  void InvalidateToken(const std::string& token) override;
+  void Register(RegisterCallback callback) override;
+  void SetMessageReceiver(MessageCallback callback) override;
 
   void RequestTokenFinished(RequestTokenCallback callback,
                             const GoogleServiceAuthError& error,