RTCPeerConnection.addTrack and removeTrack added (behind flag)

third_party/WebKit/Source/modules/peerconnection/RTCRtpSender.cpp

 // Copyright 2017 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.
 
 #include "modules/peerconnection/RTCRtpSender.h"
 
 #include "modules/mediastream/MediaStreamTrack.h"
 
 namespace blink {
 
+namespace {
+
+bool TrackEquals(const MediaStreamTrack* track,
+                 const WebMediaStreamTrack* web_track) {
+  if (track)
+    return web_track && web_track->Id() == static_cast<WebString>(track->id());

[Guido Urdaneta, 2017/07/05 15:37:06]

How does this static_cast actually work?

Shouldn't you just use WebString(track->id())?

[hbos_chromium, 2017/07/06 12:31:38]

Done.
I had to do some sort of casting because == is defined for both String and
WebString. Explicitly calling the constructor is clearer what happens, instead
of relying on static_cast to choose the operator to use, which may include both
implicit single argument constructors and operator T functions.

+  return !web_track;
+}
+
+}  // namespace
+
 RTCRtpSender::RTCRtpSender(std::unique_ptr<WebRTCRtpSender> sender,
                            MediaStreamTrack* track)
     : sender_(std::move(sender)), track_(track) {
   DCHECK(sender_);
   DCHECK(track_);
 }
 
 MediaStreamTrack* RTCRtpSender::track() {
-  DCHECK((track_ && sender_->Track() &&
-          sender_->Track()->Id() == static_cast<WebString>(track_->id())) ||
-         (!track_ && !sender_->Track()));
+  DCHECK(TrackEquals(track_, sender_->Track()));
   return track_;
 }
 
+WebRTCRtpSender* RTCRtpSender::web_rtp_sender() {
+  return sender_.get();
+}
+
+void RTCRtpSender::SetTrack(MediaStreamTrack* track) {
+  DCHECK(TrackEquals(track, sender_->Track()));
+  track_ = track;
+}
+
 DEFINE_TRACE(RTCRtpSender) {
   visitor->Trace(track_);
 }
 
 }  // namespace blink