Replace uses of raw uint32's with a type-checked RtpTimeTicks data type.

media/cast/receiver/frame_receiver.cc

Index: media/cast/receiver/frame_receiver.cc
diff --git a/media/cast/receiver/frame_receiver.cc b/media/cast/receiver/frame_receiver.cc
index b9d5a6ea6785ad11478e311a986bbe9c49dfbb1d..d7a12e68a26e9da1182e9b63955890274c04074a 100644
--- a/media/cast/receiver/frame_receiver.cc
+++ b/media/cast/receiver/frame_receiver.cc
@@ -59,7 +59,6 @@ FrameReceiver::FrameReceiver(
   DCHECK_GT(config.target_frame_rate, 0);
   decryptor_.Initialize(config.aes_key, config.aes_iv_mask);
   cast_environment_->logger()->Subscribe(&event_subscriber_);
-  memset(frame_id_to_rtp_timestamp_, 0, sizeof(frame_id_to_rtp_timestamp_));
 }
 
 FrameReceiver::~FrameReceiver() {
@@ -92,7 +91,7 @@ bool FrameReceiver::ProcessPacket(scoped_ptr<Packet> packet) {
     }
 
     ProcessParsedPacket(rtp_header, payload_data, payload_size);
-    stats_.UpdateStatistics(rtp_header);
+    stats_.UpdateStatistics(rtp_header, rtp_timebase_);
   }
 
   if (!reports_are_scheduled_) {
@@ -136,7 +135,7 @@ void FrameReceiver::ProcessParsedPacket(const RtpCastHeader& rtp_header,
   // Update lip-sync values upon receiving the first packet of each frame, or if
   // they have never been set yet.
   if (rtp_header.packet_id == 0 || lip_sync_reference_time_.is_null()) {
-    RtpTimestamp fresh_sync_rtp;
+    RtpTimeTicks fresh_sync_rtp;
     base::TimeTicks fresh_sync_reference;
     if (!rtcp_.GetLatestLipSyncTimes(&fresh_sync_rtp, &fresh_sync_reference)) {
       // HACK: The sender should have provided Sender Reports before the first
@@ -154,9 +153,10 @@ void FrameReceiver::ProcessParsedPacket(const RtpCastHeader& rtp_header,
     if (lip_sync_reference_time_.is_null()) {
       lip_sync_reference_time_ = fresh_sync_reference;
     } else {
-      lip_sync_reference_time_ += RtpDeltaToTimeDelta(
-          static_cast<int32>(fresh_sync_rtp - lip_sync_rtp_timestamp_),
-          rtp_timebase_);
+      // Note: It's okay for the conversion ToTimeDelta() to be approximate
+      // because |lip_sync_drift_| will account for accumulated errors.
+      lip_sync_reference_time_ +=
+          (fresh_sync_rtp - lip_sync_rtp_timestamp_).ToTimeDelta(rtp_timebase_);
     }
     lip_sync_rtp_timestamp_ = fresh_sync_rtp;
     lip_sync_drift_.Update(
@@ -173,7 +173,7 @@ void FrameReceiver::CastFeedback(const RtcpCastMessage& cast_message) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::MAIN));
 
   base::TimeTicks now = cast_environment_->Clock()->NowTicks();
-  RtpTimestamp rtp_timestamp =
+  RtpTimeTicks rtp_timestamp =
       frame_id_to_rtp_timestamp_[cast_message.ack_frame_id & 0xff];
 
   scoped_ptr<FrameEvent> ack_sent_event(new FrameEvent());
@@ -302,12 +302,10 @@ base::TimeTicks FrameReceiver::GetPlayoutTime(const EncodedFrame& frame) const {
     target_playout_delay = base::TimeDelta::FromMilliseconds(
         frame.new_playout_delay_ms);
   }
-  return lip_sync_reference_time_ +
-      lip_sync_drift_.Current() +
-      RtpDeltaToTimeDelta(
-          static_cast<int32>(frame.rtp_timestamp - lip_sync_rtp_timestamp_),
-          rtp_timebase_) +
-      target_playout_delay;
+  return lip_sync_reference_time_ + lip_sync_drift_.Current() +
+         (frame.rtp_timestamp - lip_sync_rtp_timestamp_)
+             .ToTimeDelta(rtp_timebase_) +
+         target_playout_delay;
 }
 
 void FrameReceiver::ScheduleNextCastMessage() {