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

media/cast/receiver/frame_receiver.h

Index: media/cast/receiver/frame_receiver.h
diff --git a/media/cast/receiver/frame_receiver.h b/media/cast/receiver/frame_receiver.h
index ec3175fffed672418bf015980bef9f571057dc68..78c6e897c11d04783eaa1d33ad4acad19e5b9708 100644
--- a/media/cast/receiver/frame_receiver.h
+++ b/media/cast/receiver/frame_receiver.h
@@ -13,6 +13,7 @@
 #include "base/time/time.h"
 #include "media/cast/cast_receiver.h"
 #include "media/cast/common/clock_drift_smoother.h"
+#include "media/cast/common/rtp_time.h"
 #include "media/cast/common/transport_encryption_handler.h"
 #include "media/cast/logging/logging_defines.h"
 #include "media/cast/net/rtcp/receiver_rtcp_event_subscriber.h"
@@ -170,12 +171,12 @@ class FrameReceiver : public RtpPayloadFeedback,
 
   // This mapping allows us to log FRAME_ACK_SENT as a frame event. In addition
   // it allows the event to be transmitted via RTCP.
-  RtpTimestamp frame_id_to_rtp_timestamp_[256];
+  RtpTimeTicks frame_id_to_rtp_timestamp_[256];
 
   // Lip-sync values used to compute the playout time of each frame from its RTP
   // timestamp.  These are updated each time the first packet of a frame is
   // received.
-  RtpTimestamp lip_sync_rtp_timestamp_;
+  RtpTimeTicks lip_sync_rtp_timestamp_;
   base::TimeTicks lip_sync_reference_time_;
   ClockDriftSmoother lip_sync_drift_;