Cast: First stab at implementing adaptive latency

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"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
 #include "media/cast/cast_config.h"
 #include "media/cast/sender/congestion_control.h"
 #include "media/cast/sender/frame_sender.h"
 
 namespace media {
 
 class VideoFrame;
 
 namespace cast {
 
 class CastTransportSender;
 class VideoEncoder;
 
+typedef base::Callback<void(base::TimeDelta)> PlayoutDelayChangeCB;
+
 // Not thread safe. Only called from the main cast thread.
 // This class owns all objects related to sending video, objects that create RTP
 // packets, congestion control, video encoder, parsing and sending of
 // RTCP packets.
 // Additionally it posts a bunch of delayed tasks to the main thread for various
 // timeouts.
 class VideoSender : public FrameSender,
                     public base::NonThreadSafe,
                     public base::SupportsWeakPtr<VideoSender> {
  public:
   VideoSender(scoped_refptr<CastEnvironment> cast_environment,
               const VideoSenderConfig& video_config,
               const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
               const CreateVideoEncodeMemoryCallback& create_video_encode_mem_cb,
-              CastTransportSender* const transport_sender);
+              CastTransportSender* const transport_sender,
+              const PlayoutDelayChangeCB& playout_delay_change_cb);
 
   virtual ~VideoSender();
 
   CastInitializationStatus InitializationResult() const {
     return cast_initialization_status_;
   }
 
   // Note: It is not guaranteed that |video_frame| will actually be encoded and
   // sent, if VideoSender detects too many frames in flight.  Therefore, clients
   // should be careful about the rate at which this method is called.
@@ skipping 17 matching lines @@
   // a hardware-based encoder.
   scoped_ptr<VideoEncoder> video_encoder_;
 
   // The number of frames queued for encoding, but not yet sent.
   int frames_in_encoder_;
 
   // 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_