Revert of Create RtcpDemuxer

webrtc/call/rsid_resolution_observer.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.
- */
-#ifndef WEBRTC_CALL_RSID_RESOLUTION_OBSERVER_H_
-#define WEBRTC_CALL_RSID_RESOLUTION_OBSERVER_H_
-
-#include <string>
-
-#include "webrtc/base/basictypes.h"
-
-namespace webrtc {
-
-// One RSID can be associated with one, and only one, SSRC, throughout a call.
-// The resolution might either happen during call setup, or during the call.
-class RsidResolutionObserver {
- public:
-  virtual ~RsidResolutionObserver() = default;
-
-  virtual void OnRsidResolved(const std::string& rsid, uint32_t ssrc) = 0;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_CALL_RSID_RESOLUTION_OBSERVER_H_