Add Thread-safe wrapper for RtcpTransceiver

Bug: webrtc:8239
Change-Id: I4cc2f7f2b27c764e1aae734f933902102b345614
Reviewed-on: https://webrtc-review.googlesource.com/21680
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20714}
diff --git a/modules/rtp_rtcp/source/rtcp_transceiver.h b/modules/rtp_rtcp/source/rtcp_transceiver.h
new file mode 100644
index 0000000..5a9998b
--- /dev/null
+++ b/modules/rtp_rtcp/source/rtcp_transceiver.h
@@ -0,0 +1,62 @@
+/*
+ *  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 MODULES_RTP_RTCP_SOURCE_RTCP_TRANSCEIVER_H_
+#define MODULES_RTP_RTCP_SOURCE_RTCP_TRANSCEIVER_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "modules/rtp_rtcp/source/rtcp_transceiver_config.h"
+#include "modules/rtp_rtcp/source/rtcp_transceiver_impl.h"
+#include "rtc_base/constructormagic.h"
+#include "rtc_base/copyonwritebuffer.h"
+#include "rtc_base/task_queue.h"
+#include "rtc_base/weak_ptr.h"
+
+namespace webrtc {
+//
+// Manage incoming and outgoing rtcp messages for multiple BUNDLED streams.
+//
+// This class is thread-safe wrapper of RtcpTransceiverImpl
+class RtcpTransceiver {
+ public:
+  explicit RtcpTransceiver(const RtcpTransceiverConfig& config);
+  ~RtcpTransceiver();
+
+  // Handles incoming rtcp packets.
+  void ReceivePacket(rtc::CopyOnWriteBuffer packet);
+
+  // Sends RTCP packets starting with a sender or receiver report.
+  void SendCompoundPacket();
+
+  // (REMB) Receiver Estimated Max Bitrate.
+  // Includes REMB in following compound packets.
+  void SetRemb(int bitrate_bps, std::vector<uint32_t> ssrcs);
+  // Stops sending REMB in following compound packets.
+  void UnsetRemb();
+
+ private:
+  rtc::TaskQueue* const task_queue_;
+  std::unique_ptr<RtcpTransceiverImpl> rtcp_transceiver_;
+  rtc::WeakPtrFactory<RtcpTransceiverImpl> ptr_factory_;
+  // TaskQueue, and thus tasks posted to it, may outlive this.
+  // Thus when Posting task class always pass copy of the weak_ptr to access
+  // the RtcpTransceiver and never guarantee it still will be alive when task
+  // runs.
+  rtc::WeakPtr<RtcpTransceiverImpl> ptr_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RtcpTransceiver);
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_RTP_RTCP_SOURCE_RTCP_TRANSCEIVER_H_