Set ViEEncoder sink_ on construction.

webrtc/call/bitrate_allocator.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.
  */
 
@@ skipping 94 matching lines @@
   ObserverAllocation NormalRateAllocation(uint32_t bitrate,
                                           uint32_t sum_min_bitrates)
       EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
 
   ObserverAllocation ZeroRateAllocation() EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
   ObserverAllocation LowRateAllocation(uint32_t bitrate)
       EXCLUSIVE_LOCKS_REQUIRED(crit_sect_);
 
   rtc::CriticalSection crit_sect_;
   // Stored in a list to keep track of the insertion order.
-  ObserverConfigList bitrate_observer_configs_;
+  ObserverConfigList bitrate_observer_configs_ GUARDED_BY(crit_sect_);
   bool enforce_min_bitrate_ GUARDED_BY(crit_sect_);
   uint32_t last_bitrate_bps_ GUARDED_BY(crit_sect_);
   uint32_t last_non_zero_bitrate_bps_ GUARDED_BY(crit_sect_);
   uint8_t last_fraction_loss_ GUARDED_BY(crit_sect_);
   int64_t last_rtt_ GUARDED_BY(crit_sect_);
 };
 }  // namespace webrtc
 #endif  // WEBRTC_CALL_BITRATE_ALLOCATOR_H_