Reland Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/api/webrtcsession_unittest.cc

 /*
  *  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.
  */
 
@@ skipping 4036 matching lines @@
 TEST_P(WebRtcSessionTest, TestSctpDataChannelOpenMessage) {
   MAYBE_SKIP_TEST(rtc::SSLStreamAdapter::HaveDtlsSrtp);
 
   InitWithDtls(GetParam());
 
   SetLocalDescriptionWithDataChannel();
   EXPECT_EQ(cricket::DCT_SCTP, data_engine_->last_channel_type());
 
   webrtc::DataChannelInit config;
   config.id = 1;
-  rtc::Buffer payload;
+  rtc::CopyOnWriteBuffer payload;
   webrtc::WriteDataChannelOpenMessage("a", config, &payload);
   cricket::ReceiveDataParams params;
   params.ssrc = config.id;
   params.type = cricket::DMT_CONTROL;
 
   cricket::DataChannel* data_channel = session_->data_channel();
   data_channel->SignalDataReceived(data_channel, params, payload);
 
   EXPECT_EQ("a", last_data_channel_label_);
   EXPECT_EQ(config.id, last_data_channel_config_.id);
@@ skipping 326 matching lines @@
 }
 
 // TODO(bemasc): Add a TestIceStatesBundle with BUNDLE enabled.  That test
 // currently fails because upon disconnection and reconnection OnIceComplete is
 // called more than once without returning to IceGatheringGathering.
 
 INSTANTIATE_TEST_CASE_P(WebRtcSessionTests,
                         WebRtcSessionTest,
                         testing::Values(ALREADY_GENERATED,
                                         DTLS_IDENTITY_STORE));