Convert remaining scoped_ptr -> std::unique_ptr in //mojo/edk (minus js).

mojo/edk/embedder/platform_channel_utils_posix.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_EDK_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
 #define MOJO_EDK_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_
 
 #include <stddef.h>
 #include <sys/types.h>  // For |ssize_t|.
 
 #include <deque>
 
-#include "base/memory/scoped_ptr.h"
 #include "mojo/edk/embedder/platform_handle.h"
 #include "mojo/edk/system/system_impl_export.h"
 
 struct iovec;  // Declared in <sys/uio.h>.
 
 namespace mojo {
 namespace embedder {
 
 // The maximum number of handles that can be sent "at once" using
 // |PlatformChannelSendmsgWithHandles()|.
@@ skipping 43 matching lines @@
 MOJO_SYSTEM_IMPL_EXPORT ssize_t
 PlatformChannelRecvmsg(PlatformHandle h,
                        void* buf,
                        size_t num_bytes,
                        std::deque<PlatformHandle>* platform_handles);
 
 }  // namespace embedder
 }  // namespace mojo
 
 #endif  // MOJO_EDK_EMBEDDER_PLATFORM_CHANNEL_UTILS_POSIX_H_