Revert of RTCRtpReceiver.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