Remove video_channel() from Session interface

remoting/protocol/video_reader.h

 // Copyright (c) 2010 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.
 
 // VideoReader is a generic interface for a video stream reader. RtpVideoReader
 // and ProtobufVideoReader implement this interface for RTP and protobuf video
 // streams. VideoReader is used by ConnectionToHost to read video stream.
 
 #ifndef REMOTING_PROTOCOL_VIDEO_READER_H_
 #define REMOTING_PROTOCOL_VIDEO_READER_H_
 
 #include "base/callback.h"
 #include "remoting/protocol/video_stub.h"
 
 namespace remoting {
 
 class ChromotocolConnection;
 
 namespace protocol {
 
 class Session;
 class SessionConfig;
 
 class VideoReader {
  public:
   static VideoReader* Create(const SessionConfig* config);
 
+  // The callback is called when initialization is finished. The
+  // parameter is set to true on success.
+  typedef base::Callback<void(bool)> InitializedCallback;
+
   virtual ~VideoReader();
 
   // Initializies the reader. Doesn't take ownership of either |connection|
   // or |video_stub|.
   virtual void Init(Session* session,
-                    VideoStub* video_stub) = 0;
+                    VideoStub* video_stub,
+                    const InitializedCallback& callback) = 0;
 
  protected:
   VideoReader() { }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VideoReader);
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_VIDEO_READER_H_