Wire up BitrateAllocation to be sent as RTCP TargetBitrate

webrtc/common_video/include/video_bitrate_allocator.h

 /*
  *  Copyright (c) 2016 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_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_
 #define WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_
 
 #include "webrtc/common_types.h"
 
 namespace webrtc {
 
 class VideoBitrateAllocator {
  public:
   VideoBitrateAllocator() {}
   virtual ~VideoBitrateAllocator() {}
 
   virtual BitrateAllocation GetAllocation(uint32_t total_bitrate,
                                           uint32_t framerate) = 0;
   virtual uint32_t GetPreferredBitrateBps(uint32_t framerate) = 0;
 };
 
+class VideoBitrateAllocationObserver {
+ public:
+  VideoBitrateAllocationObserver() {}
+  virtual ~VideoBitrateAllocationObserver() {}
+
+  virtual void OnBitrateAllocationUpdated(
+      const BitrateAllocation& allocation) = 0;
+};
+
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_VIDEO_INCLUDE_VIDEO_BITRATE_ALLOCATOR_H_