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

media/cast/net/rtp/rtp_packetizer.cc

Index: media/cast/net/rtp/rtp_packetizer.cc
diff --git a/media/cast/net/rtp/rtp_packetizer.cc b/media/cast/net/rtp/rtp_packetizer.cc
index 81bc6ddaad6250abda542996f8c8863ce9a4b17a..247eae8034334eba8394fe49d93452a7d289d66c 100644
--- a/media/cast/net/rtp/rtp_packetizer.cc
+++ b/media/cast/net/rtp/rtp_packetizer.cc
@@ -29,8 +29,6 @@ RtpPacketizer::RtpPacketizer(PacedSender* const transport,
       transport_(transport),
       packet_storage_(packet_storage),
       sequence_number_(config_.sequence_number),
-      rtp_timestamp_(0),
-      packet_id_(0),
       send_packet_count_(0),
       send_octet_count_(0) {
   DCHECK(transport) << "Invalid argument";
@@ -46,7 +44,6 @@ uint16_t RtpPacketizer::NextSequenceNumber() {
 void RtpPacketizer::SendFrameAsPackets(const EncodedFrame& frame) {
   uint16_t rtp_header_length = kRtpHeaderLength + kCastHeaderLength;
   uint16_t max_length = config_.max_payload_length - rtp_header_length - 1;
-  rtp_timestamp_ = frame.rtp_timestamp;
 
   // Split the payload evenly (round number up).
   size_t num_packets = (frame.data.size() + max_length) / max_length;
@@ -80,7 +77,8 @@ void RtpPacketizer::SendFrameAsPackets(const EncodedFrame& frame) {
     if (frame.dependency == EncodedFrame::KEY)
       byte0 |= kCastKeyFrameBitMask;
     // Extensions only go on the first packet of the frame
-    if (packet_id_ == 0)
+    const uint16_t packet_id = static_cast<uint16_t>(packets.size());
+    if (packet_id == 0)
       byte0 |= num_extensions;
     packet->data.push_back(byte0);
     packet->data.push_back(static_cast<uint8_t>(frame.frame_id));
@@ -88,11 +86,11 @@ void RtpPacketizer::SendFrameAsPackets(const EncodedFrame& frame) {
     packet->data.resize(start_size + 4);
     base::BigEndianWriter big_endian_writer(
         reinterpret_cast<char*>(&(packet->data[start_size])), 4);
-    big_endian_writer.WriteU16(packet_id_);
+    big_endian_writer.WriteU16(packet_id);
     big_endian_writer.WriteU16(static_cast<uint16_t>(num_packets - 1));
     packet->data.push_back(static_cast<uint8_t>(frame.referenced_frame_id));
     // Add extension details only on the first packet of the frame
-    if (packet_id_ == 0 && frame.new_playout_delay_ms) {
+    if (packet_id == 0 && frame.new_playout_delay_ms) {
       packet->data.push_back(kCastRtpExtensionAdaptiveLatency << 2);
       packet->data.push_back(2);  // 2 bytes
       packet->data.push_back(
@@ -107,27 +105,24 @@ void RtpPacketizer::SendFrameAsPackets(const EncodedFrame& frame) {
     data_iter += payload_length;
 
     const PacketKey key = PacedPacketSender::MakePacketKey(
-        PacketKey::RTP, frame.frame_id, config_.ssrc, packet_id_++);
+        PacketKey::RTP, frame.frame_id, config_.ssrc, packet_id);
     packets.push_back(make_pair(key, packet));
 
     // Update stats.
     ++send_packet_count_;
     send_octet_count_ += payload_length;
   }
-  DCHECK(packet_id_ == num_packets) << "Invalid state";
+  DCHECK_EQ(num_packets, packets.size()) << "Invalid state";
 
   packet_storage_->StoreFrame(frame.frame_id, packets);
 
   // Send to network.
   transport_->SendPackets(packets);
-
-  // Prepare for next frame.
-  packet_id_ = 0;
 }
 
 void RtpPacketizer::BuildCommonRTPheader(Packet* packet,
                                          bool marker_bit,
-                                         uint32_t time_stamp) {
+                                         RtpTimeTicks rtp_timestamp) {
   packet->push_back(0x80);
   packet->push_back(static_cast<uint8_t>(config_.payload_type) |
                     (marker_bit ? kRtpMarkerBitMask : 0));
@@ -136,7 +131,7 @@ void RtpPacketizer::BuildCommonRTPheader(Packet* packet,
   base::BigEndianWriter big_endian_writer(
       reinterpret_cast<char*>(&((*packet)[start_size])), 10);
   big_endian_writer.WriteU16(sequence_number_);
-  big_endian_writer.WriteU32(time_stamp);
+  big_endian_writer.WriteU32(rtp_timestamp.lower_32_bits());
   big_endian_writer.WriteU32(config_.ssrc);
   ++sequence_number_;
 }