Move IPC::MessageFilter and router to a separate file

content/renderer/media/video_capture_message_filter.cc

 // Copyright (c) 2012 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.
 
 #include "content/renderer/media/video_capture_message_filter.h"
 
 #include "content/common/media/video_capture_messages.h"
 #include "content/common/view_messages.h"
+#include "ipc/ipc_channel.h"
 
 namespace content {
 
 VideoCaptureMessageFilter::VideoCaptureMessageFilter()
     : last_device_id_(0),
       channel_(NULL) {
 }
 
 void VideoCaptureMessageFilter::AddDelegate(Delegate* delegate) {
   if (++last_device_id_ <= 0)
@@ skipping 183 matching lines @@
     const media::VideoCaptureFormats& formats_in_use) {
   Delegate* delegate = find_delegate(device_id);
   if (!delegate) {
     DLOG(WARNING) << "OnDeviceFormatInUse: unknown device";
     return;
   }
   delegate->OnDeviceFormatsInUseReceived(formats_in_use);
 }
 
 }  // namespace content