Changing UpdateStreamPacket protobuf definition for chromoting

remoting/host/encoder.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.
 
 #ifndef REMOTING_HOST_ENCODER_H_
 #define REMOTING_HOST_ENCODER_H_
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "media/base/data_buffer.h"
 #include "remoting/base/protocol/chromotocol.pb.h"
 #include "remoting/host/capturer.h"
 
 namespace media {
   class DataBuffer;
 }
 
 namespace remoting {
 
+class HostMessage;
+
 // A class to perform the task of encoding a continous stream of
 // images.
 // This class operates asynchronously to enable maximum throughput.
 class Encoder {
  public:
 
   // EncodingState is a bitfield that tracks the state of the encoding.
   // An encoding that consists of a single block could concievably be starting
   // inprogress and ended at the same time.
   enum {
     EncodingStarting = 1 << 0,
     EncodingInProgress = 1 << 1,
     EncodingEnded = 1 << 2
   };
   typedef int EncodingState;
 
   // DataAvailableCallback is called as blocks of data are made available
-  // from the encoder. The callback takes ownership of header and is
-  // responsible for deleting it.
-  typedef Callback3<const UpdateStreamPacketHeader*,
-                    const scoped_refptr<media::DataBuffer>&,
-                    EncodingState>::Type DataAvailableCallback;
+  // from the encoder. Data made available by the encoder is in the form
+  // of HostMessage to reduce the amount of memory copies.
+  // The callback takes ownership of the HostMessage and is responsible for
+  // deleting it.
+  typedef Callback2<HostMessage*, EncodingState>::Type DataAvailableCallback;
 
   virtual ~Encoder() {}
 
   // Encode an image stored in |capture_data|.
   //
   // If |key_frame| is true, the encoder should not reference
   // previous encode and encode the full frame.
   //
   // When encoded data is available, partial or full |data_available_callback|
   // is called.
   virtual void Encode(scoped_refptr<Capturer::CaptureData> capture_data,
                       bool key_frame,
                       DataAvailableCallback* data_available_callback) = 0;
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_ENCODER_H_