Cast: Make pacing controllable by the extension

media/cast/net/pacing/paced_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_NET_PACING_PACED_SENDER_H_
 #define MEDIA_CAST_NET_PACING_PACED_SENDER_H_
 
 #include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/default_tick_clock.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/net/cast_transport_config.h"
 
 namespace media {
 namespace cast {
 
+// Meant to use as defaults for pacer construction.
+static const size_t kTargetBurstSize = 10;
+static const size_t kMaxBurstSize = 20;
+
 class LoggingImpl;
 
 // Use std::pair for free comparison operators.
 // { capture_time, ssrc, packet_id }
 // The PacketKey is designed to meet two criteria:
 // 1. When we re-send the same packet again, we can use the packet key
 //    to identify it so that we can de-duplicate packets in the queue.
 // 2. The sort order of the PacketKey determines the order that packets
 //    are sent out. Using the capture_time as the first member basically
 //    means that older packets are sent first.
@@ skipping 36 matching lines @@
                                  uint16 packet_id);
 };
 
 class PacedSender : public PacedPacketSender,
                     public base::NonThreadSafe,
                     public base::SupportsWeakPtr<PacedSender> {
  public:
   // The |external_transport| should only be used by the Cast receiver and for
   // testing.
   PacedSender(
+      size_t target_burst_size,  // Should normally be kTargetBurstSize.
+      size_t max_burst_size,     // Should normally be kMaxBurstSize.
       base::TickClock* clock,
       LoggingImpl* logging,
       PacketSender* external_transport,
       const scoped_refptr<base::SingleThreadTaskRunner>& transport_task_runner);
 
   virtual ~PacedSender();
 
   // These must be called before non-RTCP packets are sent.
   void RegisterAudioSsrc(uint32 audio_ssrc);
   void RegisterVideoSsrc(uint32 video_ssrc);
@@ skipping 87 matching lines @@
                            // packet was sent.
     int64 last_byte_sent_for_audio;  // Number of bytes sent to network from
                                      // audio stream just before this packet.
   };
   typedef std::map<PacketKey, PacketSendRecord> PacketSendHistory;
   PacketSendHistory send_history_;
   PacketSendHistory send_history_buffer_;
   // Records the last byte sent for payload with a specific SSRC.
   std::map<uint32, int64> last_byte_sent_;
 
+  size_t target_burst_size_;
+  size_t max_burst_size_;
+
   // Maximum burst size for the next three bursts.
-  size_t max_burst_size_;
+  size_t current_max_burst_size_;
   size_t next_max_burst_size_;
   size_t next_next_max_burst_size_;
   // Number of packets already sent in the current burst.
   size_t current_burst_size_;
   // This is when the current burst ends.
   base::TimeTicks burst_end_;
 
   State state_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<PacedSender> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PacedSender);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_NET_PACING_PACED_SENDER_H_