[Cast] Limit frames in flight by duration, and not by number of frames.

media/cast/sender/video_sender.h

 // Copyright 2014 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 MEDIA_CAST_SENDER_VIDEO_SENDER_H_
 #define MEDIA_CAST_SENDER_VIDEO_SENDER_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 40 matching lines @@
   // sent, if VideoSender detects too many frames in flight.  Therefore, clients
   // should be careful about the rate at which this method is called.
   //
   // Note: It is invalid to call this method if InitializationResult() returns
   // anything but STATUS_VIDEO_INITIALIZED.
   void InsertRawVideoFrame(const scoped_refptr<media::VideoFrame>& video_frame,
                            const base::TimeTicks& capture_time);
 
  protected:
   virtual int GetNumberOfFramesInEncoder() const OVERRIDE;
+  virtual base::TimeDelta GetInFlightMediaDuration() const OVERRIDE;
   virtual void OnAck(uint32 frame_id) OVERRIDE;
 
  private:
   // Called when the encoder is initialized or has failed to initialize.
   void OnEncoderInitialized(
       const CastInitializationCallback& initialization_cb,
       CastInitializationStatus status);
 
   // Called by the |video_encoder_| with the next EncodedFrame to send.
   void OnEncodedVideoFrame(int encoder_bitrate,
                            scoped_ptr<EncodedFrame> encoded_frame);
 
   // Encodes media::VideoFrame images into EncodedFrames.  Per configuration,
   // this will point to either the internal software-based encoder or a proxy to
   // a hardware-based encoder.
   scoped_ptr<VideoEncoder> video_encoder_;
 
   // The number of frames queued for encoding, but not yet sent.
   int frames_in_encoder_;
 
+  // The duration of video queued for encoding, but not yet sent.
+  base::TimeDelta duration_in_encoder_;
+
+  // The timestamp of the frame that was last enqueued in |video_encoder_|.
+  base::TimeTicks last_enqueued_frame_reference_time_;
+
   // Remember what we set the bitrate to before, no need to set it again if
   // we get the same value.
   uint32 last_bitrate_;
 
   PlayoutDelayChangeCB playout_delay_change_cb_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoSender> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoSender);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_SENDER_VIDEO_SENDER_H_