Pace outgoing frames in frame scheduler to match target bitrate.

remoting/protocol/webrtc_frame_scheduler_simple.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
 #define REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_
 
 #include "remoting/protocol/webrtc_frame_scheduler.h"
 
 #include "base/timer/timer.h"
+#include "remoting/base/leaky_bucket.h"
 #include "remoting/base/running_samples.h"
 
 namespace remoting {
 namespace protocol {
 
 // WebrtcFrameSchedulerSimple is a simple implementation of
 // WebrtcFrameScheduler that always keeps only one frame in the pipeline.
 // It schedules each frame after the previous one is expected to finish sending.
 class WebrtcFrameSchedulerSimple : public WebrtcFrameScheduler {
  public:
   WebrtcFrameSchedulerSimple();
   ~WebrtcFrameSchedulerSimple() override;
 
   // WebrtcFrameScheduler implementation.
   void Start(const base::Closure& capture_callback) override;
   void Pause(bool pause) override;
   void SetKeyFrameRequest() override;
   void SetTargetBitrate(int bitrate_kbps) override;
   bool GetEncoderFrameParams(
       const webrtc::DesktopFrame& frame,
       WebrtcVideoEncoder::FrameParams* params_out) override;
   void OnFrameEncoded(
       const WebrtcVideoEncoder::EncodedFrame& encoded_frame,
       const webrtc::EncodedImageCallback::Result& send_result) override;
 
  private:
-  void ScheduleNextFrame();
+  void ScheduleNextFrame(base::TimeTicks now);
   void CaptureNextFrame();
 
   base::Closure capture_callback_;
   bool paused_ = false;
   bool key_frame_request_ = false;
-  int target_bitrate_kbps_ = 1000;  // Initial bitrate.
 
   base::TimeTicks last_capture_started_time_;
-  base::TimeTicks last_frame_send_finish_time_;
+
+  LeakyBucket pacing_bucket_;
 
   // Set to true when encoding unchanged frames for top-off.
   bool top_off_is_active_ = false;
 
   // Accumulator for capture and encoder delay history.
   RunningSamples frame_processing_delay_us_;
 
   base::OneShotTimer capture_timer_;
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_WEBRTC_FRAME_SCHEDULER_SIMPLE_H_