Create skeleton of the rtcp transceiver.

RtcpTransceiver name reserved for thread-safe version that planned to
be wrapper of the RtcpTransceiverImpl

BUG=webrtc:8239

Change-Id: If8a3092eb1b8e4175e3efd23b52e1043cdabf19f
Reviewed-on: https://webrtc-review.googlesource.com/7920
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20414}

modules/rtp_rtcp/source/rtcp_transceiver_config.h

@@ -0,0 +1,54 @@
+/*
+ *  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_CONFIG_H_
+#define MODULES_RTP_RTCP_SOURCE_RTCP_TRANSCEIVER_CONFIG_H_
+
+#include <string>
+
+namespace webrtc {
+class ReceiveStatisticsProvider;
+class Transport;
+
+struct RtcpTransceiverConfig {
+  RtcpTransceiverConfig();
+  RtcpTransceiverConfig(const RtcpTransceiverConfig&);
+  RtcpTransceiverConfig& operator=(const RtcpTransceiverConfig&);
+  ~RtcpTransceiverConfig();
+
+  // Logs the error and returns false if configuration miss key objects or
+  // is inconsistant. May log warnings.
+  bool Validate() const;
+
+  // Used to prepend all log messages. Can be empty.
+  std::string debug_id;
+
+  // Ssrc to use as default sender ssrc, e.g. for transport-wide feedbacks.
+  uint32_t feedback_ssrc = 1;
+
+  // Cname of the local particiapnt.
+  std::string cname;
+
+  // Maximum packet size outgoing transport accepts.
+  size_t max_packet_size = 1200;
+
+  // Transport to send rtcp packets to. Should be set.
+  Transport* outgoing_transport = nullptr;
+
+  // Minimum period to send receiver reports and attached messages.
+  int min_periodic_report_ms = 1000;
+
+  // Rtcp report block generator for outgoing receiver reports.
+  ReceiveStatisticsProvider* receive_statistics = nullptr;
+};
+
+}  // namespace webrtc
+
+#endif  // MODULES_RTP_RTCP_SOURCE_RTCP_TRANSCEIVER_CONFIG_H_