Misc truncation fixes for gn builds with VS 2015

chrome/browser/media/webrtc_rtp_dump_writer.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 "chrome/browser/media/webrtc_rtp_dump_writer.h"
 
 #include "base/big_endian.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 288 matching lines @@
     WriteRtpDumpFileHeaderBigEndian(start_time_, dest_buffer);
   }
 
   size_t packet_dump_length = kPacketDumpHeaderSize + header_length;
 
   // Flushes the buffer to disk if the buffer is full.
   if (dest_buffer->size() + packet_dump_length > dest_buffer->capacity())
     FlushBuffer(incoming, false, FlushDoneCallback());
 
   WritePacketDumpHeaderBigEndian(
-      start_time_, packet_dump_length, packet_length, dest_buffer);
+      start_time_, base::checked_cast<uint16>(packet_dump_length),
+      base::checked_cast<uint16>(packet_length), dest_buffer);
 
   // Writes the actual RTP packet header.
   AppendToBuffer(packet_header, header_length, dest_buffer);
 }
 
 void WebRtcRtpDumpWriter::EndDump(RtpDumpType type,
                                   const EndDumpCallback& finished_callback) {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(type == RTP_DUMP_OUTGOING || incoming_file_thread_worker_ != NULL);
   DCHECK(type == RTP_DUMP_INCOMING || outgoing_file_thread_worker_ != NULL);
@@ skipping 117 matching lines @@
                 base::Bind(&WebRtcRtpDumpWriter::OnDumpEnded,
                            weak_ptr_factory_.GetWeakPtr(),
                            context,
                            false));
     return;
   }
 
   // This object might be deleted after running the callback.
   context.callback.Run(context.incoming_succeeded, context.outgoing_succeeded);
 }