Refactor RtpSender and SSRCDatabase a bit.

webrtc/modules/rtp_rtcp/source/rtp_sender.h

Index: webrtc/modules/rtp_rtcp/source/rtp_sender.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.h b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
index a672a06398a5772b9ef64914914a5946e8410536..346039380b56ff630a3823cc306ec039df8bfaac 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.h
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.h
@@ -16,8 +16,10 @@
 #include <utility>
 #include <vector>
 
+#include "webrtc/base/criticalsection.h"
 #include "webrtc/base/random.h"
 #include "webrtc/base/thread_annotations.h"
+#include "webrtc/base/thread_checker.h"
 #include "webrtc/common_types.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/bitrate.h"
@@ -30,12 +32,42 @@
 
 namespace webrtc {
 
-class BitrateAggregator;
-class CriticalSectionWrapper;
 class RTPSenderAudio;
 class RTPSenderVideo;
 class RtcEventLog;
 
+class BitrateAggregator {
+ public:
+  explicit BitrateAggregator(BitrateStatisticsObserver* bitrate_callback);
+
+  void OnStatsUpdated() const;
+
+  Bitrate::Observer* total_bitrate_observer();
+  Bitrate::Observer* retransmit_bitrate_observer();
+  void set_ssrc(uint32_t ssrc);
+
+ private:
+  // We assume that these observers are called on the same thread, which is
+  // true for RtpSender as they are called on the Process thread.
+  class BitrateObserver : public Bitrate::Observer {
+   public:
+    explicit BitrateObserver(const BitrateAggregator& aggregator);
+
+    // Implements Bitrate::Observer.
+    void BitrateUpdated(const BitrateStatistics& stats) override;
+    BitrateStatistics statistics() const;
+
+   private:
+    BitrateStatistics statistics_;
+    const BitrateAggregator& aggregator_;
+  };
+
+  BitrateStatisticsObserver* const callback_;
+  BitrateObserver total_bitrate_observer_;
+  BitrateObserver retransmit_bitrate_observer_;
+  uint32_t ssrc_;
+};
+
 class RTPSenderInterface {
  public:
   RTPSenderInterface() {}
@@ -98,7 +130,8 @@ class RTPSender : public RTPSenderInterface {
             BitrateStatisticsObserver* bitrate_callback,
             FrameCountObserver* frame_count_observer,
             SendSideDelayObserver* send_side_delay_observer,
-            RtcEventLog* event_log);
+            RtcEventLog* event_log,
+            SSRCDatabase* ssrc_database);
   virtual ~RTPSender();
 
   void ProcessBitrate();
@@ -196,7 +229,7 @@ class RTPSender : public RTPSenderInterface {
                                   const RTPHeader& rtp_header,
                                   size_t extension_length_bytes,
                                   size_t* extension_offset) const
-      EXCLUSIVE_LOCKS_REQUIRED(send_critsect_.get());
+      EXCLUSIVE_LOCKS_REQUIRED(send_critsect_);
 
   bool UpdateAudioLevel(uint8_t* rtp_packet,
                         size_t rtp_packet_length,
@@ -386,22 +419,22 @@ class RTPSender : public RTPSenderInterface {
                       bool is_retransmit);
   bool IsFecPacket(const uint8_t* buffer, const RTPHeader& header) const;
 
-  Clock* clock_;
-  int64_t clock_delta_ms_;
+  Clock* const clock_;
+  const int64_t clock_delta_ms_;
   Random random_ GUARDED_BY(send_critsect_);
 
-  rtc::scoped_ptr<BitrateAggregator> bitrates_;
+  BitrateAggregator bitrates_;
   Bitrate total_bitrate_sent_;
 
   const bool audio_configured_;
-  rtc::scoped_ptr<RTPSenderAudio> audio_;
-  rtc::scoped_ptr<RTPSenderVideo> video_;
+  const rtc::scoped_ptr<RTPSenderAudio> audio_;
+  const rtc::scoped_ptr<RTPSenderVideo> video_;
 
   RtpPacketSender* const paced_sender_;
   TransportSequenceNumberAllocator* const transport_sequence_number_allocator_;
   TransportFeedbackObserver* const transport_feedback_observer_;
   int64_t last_capture_time_ms_sent_;
-  rtc::scoped_ptr<CriticalSectionWrapper> send_critsect_;
+  rtc::CriticalSection send_critsect_;
 
   Transport *transport_;
   bool sending_media_ GUARDED_BY(send_critsect_);
@@ -440,7 +473,7 @@ class RTPSender : public RTPSenderInterface {
   // RTP variables
   bool start_timestamp_forced_ GUARDED_BY(send_critsect_);
   uint32_t start_timestamp_ GUARDED_BY(send_critsect_);
-  SSRCDatabase& ssrc_db_ GUARDED_BY(send_critsect_);
+  SSRCDatabase* const ssrc_db_;
   uint32_t remote_ssrc_ GUARDED_BY(send_critsect_);
   bool sequence_number_forced_ GUARDED_BY(send_critsect_);
   uint16_t sequence_number_ GUARDED_BY(send_critsect_);
@@ -467,6 +500,7 @@ class RTPSender : public RTPSenderInterface {
   // that the target bitrate is still valid.
   rtc::scoped_ptr<CriticalSectionWrapper> target_bitrate_critsect_;
   uint32_t target_bitrate_ GUARDED_BY(target_bitrate_critsect_);
+  rtc::ThreadChecker thread_checker_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RTPSender);
 };