Remove webrtc/stream.h and unutilized inheritance.

webrtc/stream.h

-/*
- *  Copyright (c) 2015 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_STREAM_H_
-#define WEBRTC_STREAM_H_
-
-#include "webrtc/common_types.h"
-
-namespace webrtc {
-
-enum NetworkState {
-  kNetworkUp,
-  kNetworkDown,
-};
-
-// Common base class for streams.
-class Stream {
- public:
-  // Starts stream activity.
-  // When a stream is active, it can receive, process and deliver packets.
-  virtual void Start() = 0;
-  // Stops stream activity.
-  // When a stream is stopped, it can't receive, process or deliver packets.
-  virtual void Stop() = 0;
-  // Called to notify that network state has changed, so that the stream can
-  // respond, e.g. by pausing or resuming activity.
-  virtual void SignalNetworkState(NetworkState state) = 0;
-  // Called when a RTCP packet is received.
-  virtual bool DeliverRtcp(const uint8_t* packet, size_t length) = 0;
-
- protected:
-  virtual ~Stream() {}
-};
-
-// Common base class for receive streams.
-class ReceiveStream : public Stream {
- public:
-  // Called when a RTP packet is received.
-  virtual bool DeliverRtp(const uint8_t* packet,
-                          size_t length,
-                          const PacketTime& packet_time) = 0;
-};
-
-// Common base class for send streams.
-// A tag class that denotes send stream type.
-class SendStream : public Stream {};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_STREAM_H_