EDK: Convert remaining scoped_ptr -> std::unique_ptr in //mojo/edk/system.

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/memory/ref_counted.h"
 #include "mojo/edk/system/message_in_transit.h"
 #include "mojo/edk/system/message_pipe_endpoint.h"
@@ skipping 26 matching lines @@
   // may be called at most once, after which |Close()| need not be called.
   //
   // Note: The returned |ChannelEndpoint| must have its client changed while
   // still under |MessagePipe|'s lock (which this must have also been called
   // under).
   scoped_refptr<ChannelEndpoint> ReleaseChannelEndpoint();
 
   // |MessagePipeEndpoint| implementation:
   Type GetType() const override;
   bool OnPeerClose() override;
-  void EnqueueMessage(scoped_ptr<MessageInTransit> message) override;
+  void EnqueueMessage(std::unique_ptr<MessageInTransit> message) override;
   void Close() override;
 
  private:
   void DetachIfNecessary();
 
   scoped_refptr<ChannelEndpoint> channel_endpoint_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(ProxyMessagePipeEndpoint);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_PROXY_MESSAGE_PIPE_ENDPOINT_H_