Standardize usage of virtual/override/final in mojo/

mojo/public/cpp/application/lib/weak_service_provider.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 MOJO_PUBLIC_APPLICATION_LIB_WEAK_SERVICE_PROVIDER_H_
 #define MOJO_PUBLIC_APPLICATION_LIB_WEAK_SERVICE_PROVIDER_H_
 
 #include "mojo/public/interfaces/application/service_provider.mojom.h"
 
 namespace mojo {
 class ServiceProviderImpl;
 namespace internal {
 class ServiceConnectorBase;
 
 // Implements a weak pointer to a ServiceProvider. Necessary as the lifetime of
 // the ServiceProviderImpl is bound to that of its pipe, but code may continue
 // to reference a remote service provider beyond the lifetime of said pipe.
 // Calls to ConnectToService() are silently dropped when the pipe is closed.
 class WeakServiceProvider : public ServiceProvider {
  public:
   WeakServiceProvider(ServiceProviderImpl* creator,
                       ServiceProvider* service_provider);
-  virtual ~WeakServiceProvider();
+  ~WeakServiceProvider() override;
 
   void Clear();
 
  private:
   // Overridden from ServiceProvider:
-  virtual void ConnectToService(const String& service_name,
-                                ScopedMessagePipeHandle client_handle) override;
+  void ConnectToService(const String& service_name,
+                        ScopedMessagePipeHandle client_handle) override;
 
   ServiceProviderImpl* creator_;
   ServiceProvider* service_provider_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(WeakServiceProvider);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_APPLICATION_LIB_WEAK_SERVICE_PROVIDER_H_