Web MIDI: prepare to pass a security origin from blink to browser

content/common/media/midi_messages.h

 // Copyright (c) 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.
 
 // IPC messages for access to MIDI hardware.
 // Multiply-included message file, hence no include guard.
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/midi/midi_port_info.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START MIDIMsgStart
 
 IPC_STRUCT_TRAITS_BEGIN(media::MIDIPortInfo)
   IPC_STRUCT_TRAITS_MEMBER(id)
   IPC_STRUCT_TRAITS_MEMBER(manufacturer)
   IPC_STRUCT_TRAITS_MEMBER(name)
   IPC_STRUCT_TRAITS_MEMBER(version)
 IPC_STRUCT_TRAITS_END()
 
 // Renderer request to browser for access to MIDI services.
-IPC_MESSAGE_CONTROL2(MIDIHostMsg_RequestAccess,
+IPC_MESSAGE_CONTROL3(MIDIHostMsg_RequestAccess,
+                     std::string /* origin */,
                      int /* client id */,
                      int /* access */)
 
 IPC_MESSAGE_CONTROL3(MIDIHostMsg_SendData,
                      int /* port */,
                      std::vector<uint8> /* data */,
                      double /* timestamp */)
 
 // Messages sent from the browser to the renderer.
 
 IPC_MESSAGE_CONTROL5(MIDIMsg_AccessApproved,
                      int /* client id */,
                      int /* access */,
                      bool /* success */,
                      media::MIDIPortInfoList /* input ports */,
                      media::MIDIPortInfoList /* output ports */)
 
 IPC_MESSAGE_CONTROL3(MIDIMsg_DataReceived,
                      int /* port */,
                      std::vector<uint8> /* data */,
                      double /* timestamp */)