Reland of TCRtpReceiver.getContributingSources() added.

third_party/WebKit/Source/modules/peerconnection/RTCRtpContributingSource.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 RTCRtpContributingSource_h
+#define RTCRtpContributingSource_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "platform/heap/GarbageCollected.h"
+#include "platform/heap/Member.h"
+#include "platform/heap/Visitor.h"
+
+namespace blink {
+
+class RTCRtpReceiver;
+class WebRTCRtpContributingSource;
+
+// https://w3c.github.io/webrtc-pc/#dom-rtcrtpcontributingsource
+class RTCRtpContributingSource final
+    : public GarbageCollectedFinalized<RTCRtpContributingSource>,
+      public ScriptWrappable {
+  DEFINE_WRAPPERTYPEINFO();
+
+ public:
+  RTCRtpContributingSource(RTCRtpReceiver*, const WebRTCRtpContributingSource&);
+  // The source's source ID must match |source|.
+  void UpdateMembers(const WebRTCRtpContributingSource&);
+
+  double timestamp();
+  uint32_t source() const;
+
+  DECLARE_VIRTUAL_TRACE();
+
+ private:
+  Member<RTCRtpReceiver> receiver_;
+  double timestamp_ms_;
+  const uint32_t source_;
+};
+
+}  // namespace blink
+
+#endif  // RTCRtpContributingSource_h