Reland of Initialize/configure video encoders asychronously.

webrtc/video/video_send_stream.h

 /*
  *  Copyright (c) 2013 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_VIDEO_VIDEO_SEND_STREAM_H_
 #define WEBRTC_VIDEO_VIDEO_SEND_STREAM_H_
 
 #include <map>
 #include <vector>
 
 #include "webrtc/call/bitrate_allocator.h"
+#include "webrtc/base/criticalsection.h"
 #include "webrtc/call.h"
 #include "webrtc/common_video/libyuv/include/webrtc_libyuv.h"
 #include "webrtc/video/encoded_frame_callback_adapter.h"
 #include "webrtc/video/encoder_state_feedback.h"
 #include "webrtc/video/payload_router.h"
 #include "webrtc/video/send_statistics_proxy.h"
 #include "webrtc/video/video_capture_input.h"
 #include "webrtc/video/vie_channel.h"
 #include "webrtc/video/vie_encoder.h"
 #include "webrtc/video_receive_stream.h"
@@ skipping 55 matching lines @@
                         int64_t rtt) override;
 
   // Implements webrtc::VCMProtectionCallback.
   int ProtectionRequest(const FecProtectionParams* delta_params,
                         const FecProtectionParams* key_params,
                         uint32_t* sent_video_rate_bps,
                         uint32_t* sent_nack_rate_bps,
                         uint32_t* sent_fec_rate_bps) override;
 
  private:
+  struct EncoderSettings {
+    VideoCodec video_codec;
+    int min_transmit_bitrate_bps;
+  };
   static bool EncoderThreadFunction(void* obj);
   void EncoderProcess();
 
   void ConfigureProtection();
   void ConfigureSsrcs();
 
   SendStatisticsProxy stats_proxy_;
   EncodedFrameCallbackAdapter encoded_frame_proxy_;
   const VideoSendStream::Config config_;
   std::map<uint32_t, RtpState> suspended_ssrcs_;
 
   ProcessThread* const module_process_thread_;
   CallStats* const call_stats_;
   CongestionController* const congestion_controller_;
   BitrateAllocator* const bitrate_allocator_;
   VieRemb* const remb_;
 
   rtc::PlatformThread encoder_thread_;
   rtc::Event encoder_wakeup_event_;
   volatile int stop_encoder_thread_;
+  rtc::CriticalSection encoder_settings_crit_;
+  rtc::Optional<EncoderSettings> pending_encoder_settings_
+      GUARDED_BY(encoder_settings_crit_);
 
   OveruseFrameDetector overuse_detector_;
   EncoderStateFeedback encoder_feedback_;
   ViEEncoder vie_encoder_;
   VideoCodingModule* const vcm_;
 
   const std::unique_ptr<RtcpBandwidthObserver> bandwidth_observer_;
   // RtpRtcp modules, declared here as they use other members on construction.
   const std::vector<RtpRtcp*> rtp_rtcp_modules_;
   PayloadRouter payload_router_;
   VideoCaptureInput input_;
 };
 }  // namespace internal
 }  // namespace webrtc
 
 #endif  // WEBRTC_VIDEO_VIDEO_SEND_STREAM_H_