Add comments for struct members that were changed from size_t to uin32_t or uint64_t for IPC safety.

media/cast/receiver/frame_receiver.cc

 // 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.
 
 #include "media/cast/receiver/frame_receiver.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/big_endian.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_conversions.h"
 #include "media/cast/cast_config.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/cast_environment.h"
 #include "media/cast/constants.h"
 #include "media/cast/net/rtcp/rtcp_utility.h"
 
 namespace {
 
 const int kMinSchedulingDelayMs = 1;
 
@@ skipping 98 matching lines @@
       rtp_header.rtp_timestamp;
 
   scoped_ptr<PacketEvent> receive_event(new PacketEvent());
   receive_event->timestamp = now;
   receive_event->type = PACKET_RECEIVED;
   receive_event->media_type = event_media_type_;
   receive_event->rtp_timestamp = rtp_header.rtp_timestamp;
   receive_event->frame_id = rtp_header.frame_id;
   receive_event->packet_id = rtp_header.packet_id;
   receive_event->max_packet_id = rtp_header.max_packet_id;
-  receive_event->size = payload_size;
+  receive_event->size = base::checked_cast<uint32_t>(payload_size);
   cast_environment_->logger()->DispatchPacketEvent(std::move(receive_event));
 
   bool duplicate = false;
   const bool complete =
       framer_.InsertPacket(payload_data, payload_size, rtp_header, &duplicate);
 
   // Duplicate packets are ignored.
   if (duplicate)
     return;
 
@@ skipping 206 matching lines @@
   const base::TimeTicks now = cast_environment_->Clock()->NowTicks();
   RtpReceiverStatistics stats = stats_.GetStatistics();
   transport_->SendRtcpFromRtpReceiver(rtcp_.local_ssrc(), rtcp_.remote_ssrc(),
                                       CreateRtcpTimeData(now), NULL,
                                       base::TimeDelta(), NULL, &stats);
   ScheduleNextRtcpReport();
 }
 
 }  // namespace cast
 }  // namespace media