Interface RTCRtpReceiver and RTCPeerConnection.getReceivers() added.

third_party/WebKit/Source/modules/peerconnection/RTCRtpReceiver.h

+// 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.
+
+#ifndef RTCRtpReceiver_h
+#define RTCRtpReceiver_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "modules/mediastream/MediaStreamTrack.h"
+#include "platform/heap/GarbageCollected.h"
+#include "platform/heap/Member.h"
+#include "platform/heap/Visitor.h"
+#include "public/platform/WebRTCRtpReceiver.h"
+#include "wtf/text/WTFString.h"
+
+namespace blink {
+
+// https://w3c.github.io/webrtc-pc/#rtcrtpreceiver-interface
+class RTCRtpReceiver final : public GarbageCollectedFinalized<RTCRtpReceiver>,

[Taylor_Brandstetter, 2017/03/24 18:13:07]

Is there any way this and WebRTCRtpReceiver could be combined into the same
object? I just counted and, with this CL, we'll end up with 10 different
"RtpReceiver" interfaces at different layers.

If it's not possible today with how blink/chromium interact with each other,
will it ever be possible?

[hbos_chromium, 2017/03/27 14:55:19]

It has to do with how blink/chromium/webrtc layers interact with each other,
it's horrible and confusing...
- You need a blink class for the JavaScript object (RTCRtpReceiver.idl/h/cpp).
- You need an interface for content to implement because blink can't touch
webrtc directly (WebRTCRtpReceiver.h/cpp).
- You need the implementation of the interface in content that interacts with
webrtc (rtc_rtp_receiver.h/cc).
- You need the webrtc interface (rtpreceiverinterface.h) and webrtc-layer impls
(audio, video, proxy, blah).

There are plans to change the DEPS to allow blink to touch webrtc code directly,
ultimately getting rid of the content/renderer layer. That would allow us to
only have:
- blink::RTCRtpReceiver
- webrtc::RtpReceiverInterface (and impls)
I'm looking forward to that. But for now that is not possible.

guidou do you know what the plan is with that? Is there anything blocking that?

[Taylor_Brandstetter, 2017/03/27 21:39:02]

That answers my question; thanks! Does this plan have an associated bug so I can
follow along?

+                             public ScriptWrappable {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  // Takes ownership of the receiver.
+  RTCRtpReceiver(std::unique_ptr<WebRTCRtpReceiver>, MediaStreamTrack*);
+
+  MediaStreamTrack* track() const;
+
+  DECLARE_VIRTUAL_TRACE();
+
+ private:
+  std::unique_ptr<WebRTCRtpReceiver> m_receiver;
+  Member<MediaStreamTrack> m_track;
+};
+
+}  // namespace blink
+
+#endif  // RTCRtpReceiver_h