Implement GpuArcVideoService for arc video accelerator

components/arc/common/arc_instance_messages.h

 // Copyright 2015 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.
 
 // Messages sent from the host to the ARC instance.
 // Multiply-included message file, hence no include guard.
 
 #include <stdint.h>
 
 #include "base/file_descriptor_posix.h"
 #include "ipc/ipc_message_macros.h"
+#include "ipc/ipc_channel_handle.h"
 
 #define IPC_MESSAGE_START ArcInstanceMsgStart
 
 // Registers a virtual input device on the container side.
 // |name| is the device name, like "Chrome OS Keyboard".
 // |device_type| is the device type, like "keyboard".
 // The virtual device will be reading 'struct input_event's from |fd|.  The
 // ownership of |fd| will be transferred to the receiver, so the sender must
 // not close it.
 IPC_MESSAGE_CONTROL3(ArcInstanceMsg_RegisterInputDevice,
                      std::string, /* name */
                      std::string, /* device_type */
                      base::FileDescriptor /* fd */)
+
+IPC_MESSAGE_CONTROL1(ArcInstanceMsg_NotifyVideoAcceleratorConnecitonCreated,
+                     IPC::ChannelHandle /* handle */)