Standardize usage of virtual/override/final in mojo/

mojo/edk/system/proxy_message_pipe_endpoint.h

 // Copyright 2013 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_EDK_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 #define MOJO_EDK_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "mojo/edk/system/message_in_transit.h"
@@ skipping 13 matching lines @@
 // |MessagePipe|.
 //
 // For example, a |MessagePipe| with one endpoint local and the other endpoint
 // remote consists of a |LocalMessagePipeEndpoint| and a
 // |ProxyMessagePipeEndpoint|, with only the local endpoint being accessible via
 // a |MessagePipeDispatcher|.
 class MOJO_SYSTEM_IMPL_EXPORT ProxyMessagePipeEndpoint
     : public MessagePipeEndpoint {
  public:
   explicit ProxyMessagePipeEndpoint(ChannelEndpoint* channel_endpoint);
-  virtual ~ProxyMessagePipeEndpoint();
+  ~ProxyMessagePipeEndpoint() override;
 
   // |MessagePipeEndpoint| implementation:
-  virtual Type GetType() const override;
-  virtual bool OnPeerClose() override;
-  virtual void EnqueueMessage(scoped_ptr<MessageInTransit> message) override;
-  virtual void Close() override;
+  Type GetType() const override;
+  bool OnPeerClose() override;
+  void EnqueueMessage(scoped_ptr<MessageInTransit> message) override;
+  void Close() override;
 
  private:
   void DetachIfNecessary();
 
   scoped_refptr<ChannelEndpoint> channel_endpoint_;
 
   DISALLOW_COPY_AND_ASSIGN(ProxyMessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_