Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/api/datachannelinterface.h

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 // This file contains interfaces for DataChannels
 // http://dev.w3.org/2011/webrtc/editor/webrtc.html#rtcdatachannel
 
 #ifndef WEBRTC_API_DATACHANNELINTERFACE_H_
 #define WEBRTC_API_DATACHANNELINTERFACE_H_
 
 #include <string>
 
 #include "webrtc/base/basictypes.h"
-#include "webrtc/base/buffer.h"
 #include "webrtc/base/checks.h"
+#include "webrtc/base/copyonwritebuffer.h"
 #include "webrtc/base/refcount.h"
 
 
 namespace webrtc {
 
 struct DataChannelInit {
   DataChannelInit()
       : reliable(false),
         ordered(true),
         maxRetransmitTime(-1),
@@ skipping 11 matching lines @@
   std::string protocol;    // This is set by the application and opaque to the
                            // WebRTC implementation.
   bool negotiated;         // True if the channel has been externally negotiated
                            // and we do not send an in-band signalling in the
                            // form of an "open" message.
   int id;                  // The stream id, or SID, for SCTP data channels. -1
                            // if unset.
 };
 
 struct DataBuffer {
-  DataBuffer(const rtc::Buffer& data, bool binary)
+  DataBuffer(const rtc::CopyOnWriteBuffer& data, bool binary)
       : data(data),
         binary(binary) {
   }
   // For convenience for unit tests.
   explicit DataBuffer(const std::string& text)
       : data(text.data(), text.length()),
         binary(false) {
   }
   size_t size() const { return data.size(); }
 
-  rtc::Buffer data;
+  rtc::CopyOnWriteBuffer data;
   // Indicates if the received data contains UTF-8 or binary data.
   // Note that the upper layers are left to verify the UTF-8 encoding.
   // TODO(jiayl): prefer to use an enum instead of a bool.
   bool binary;
 };
 
 class DataChannelObserver {
  public:
   // The data channel state have changed.
   virtual void OnStateChange() = 0;
@@ skipping 58 matching lines @@
   // Sends |data| to the remote peer.
   virtual bool Send(const DataBuffer& buffer) = 0;
 
  protected:
   virtual ~DataChannelInterface() {}
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_DATACHANNELINTERFACE_H_