Make FlexFEC packets paceable through RTPSender.

webrtc/modules/rtp_rtcp/include/rtp_rtcp.h

 /*
  *  Copyright (c) 2012 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_MODULES_RTP_RTCP_INCLUDE_RTP_RTCP_H_
 #define WEBRTC_MODULES_RTP_RTCP_INCLUDE_RTP_RTCP_H_
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/deprecation.h"
+#include "webrtc/base/optional.h"
 #include "webrtc/modules/include/module.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/video_coding/include/video_coding_defines.h"
 
 namespace webrtc {
 
 // Forward declarations.
 class RateLimiter;
 class ReceiveStatistics;
 class RemoteBitrateEstimator;
@@ skipping 164 matching lines @@
 
   // Sets the SSRC to use when sending RTX packets. This doesn't enable RTX,
   // only the SSRC is set.
   virtual void SetRtxSsrc(uint32_t ssrc) = 0;
 
   // Sets the payload type to use when sending RTX packets. Note that this
   // doesn't enable RTX, only the payload type is set.
   virtual void SetRtxSendPayloadType(int payload_type,
                                      int associated_payload_type) = 0;
 
+  // Returns the FlexFEC SSRC, if there is one.
+  virtual rtc::Optional<uint32_t> FlexfecSsrc() const = 0;
+
   // Sets sending status. Sends kRtcpByeCode when going from true to false.
   // Returns -1 on failure else 0.
   virtual int32_t SetSendingStatus(bool sending) = 0;
 
   // Returns current sending status.
   virtual bool Sending() const = 0;
 
   // Starts/Stops media packets. On by default.
   virtual void SetSendingMediaStatus(bool sending) = 0;
 
@@ skipping 251 matching lines @@
   virtual int32_t SetKeyFrameRequestMethod(KeyFrameRequestMethod method) = 0;
 
   // Sends a request for a keyframe.
   // Returns -1 on failure else 0.
   virtual int32_t RequestKeyFrame() = 0;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_RTP_RTCP_INCLUDE_RTP_RTCP_H_