Move ownership of RtpTransportControllerSendInterface from Call to PeerConnection.

webrtc/call/rtp_transport_controller_send.h

 /*
  *  Copyright (c) 2017 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 20 matching lines @@
   SendSideCongestionController* send_side_cc() override {
     return &send_side_cc_;
   }
   TransportFeedbackObserver* transport_feedback_observer() override {
     return &send_side_cc_;
   }
   RtpPacketSender* packet_sender() override { return send_side_cc_.pacer(); }
 
  private:
   PacketRouter packet_router_;
+  // TODO(nisse): Should have a pointer to the
+  // SendSideCongestionController, to be able to share it between
+  // multiple transports. Unclear if the PacketRouter should be shared
+  // as well?
   SendSideCongestionController send_side_cc_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(RtpTransportControllerSend);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_