Clean up type usage and fix MSVC "truncated value" warnings in net/quic/.

net/quic/quic_protocol.h

 // Copyright (c) 2012 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.
 
 #ifndef NET_QUIC_QUIC_PROTOCOL_H_
 #define NET_QUIC_QUIC_PROTOCOL_H_
 
 #include <stddef.h>
 #include <limits>
 #include <list>
@@ skipping 1071 matching lines @@
                    QuicSequenceNumberLength sequence_number_length,
                    TransmissionType transmission_type,
                    QuicTime sent_time);
 
   RetransmittableFrames* retransmittable_frames;
   QuicSequenceNumberLength sequence_number_length;
   // Zero when the packet is serialized, non-zero once it's sent.
   QuicTime sent_time;
   // Zero when the packet is serialized, non-zero once it's sent.
   QuicByteCount bytes_sent;
-  size_t nack_count;
+  QuicPacketCount nack_count;
   // Reason why this packet was transmitted.
   TransmissionType transmission_type;
   // Stores the sequence numbers of all transmissions of this packet.
   // Must always be nullptr or have multiple elements.
   SequenceNumberList* all_transmissions;
   // In flight packets have not been abandoned or lost.
   bool in_flight;
   // True if the packet can never be acked, so it can be removed.
   bool is_unackable;
   // True if the packet is an FEC packet.
   bool is_fec_packet;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_PROTOCOL_H_