Fix "conversion of size_t to unsigned int" warning

net/dns/record_rdata.cc

 // Copyright (c) 2013 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 "net/dns/record_rdata.h"
 
 #include "base/big_endian.h"
 #include "net/dns/dns_protocol.h"
 #include "net/dns/dns_response.h"
 
@@ skipping 241 matching lines @@
                         bitmap_data.begin(),
                         bitmap_data.end());
 
   return rdata;
 }
 
 uint16_t NsecRecordRdata::Type() const {
   return NsecRecordRdata::kType;
 }
 
+uint16_t NsecRecordRdata::bitmap_length() const {
+  DCHECK_LE(bitmap_.size(), 32u);

[Ryan Sleevi, 2016/07/06 15:28:58]

It's unclear if you added this DCHECK as documentary purposes (this is
guaranteed) or as a guard against developer mistake ("size should be less than
32")

If the latter, it's a bad guard - because this is handling untrusted data,
there's no way the caller could validate/preprocess the data to make sure that
this was true.

If the former, it's not sufficient documentation - because I still had to try to
figure out which it was, and why it was safe to document this. (For the record,
it's because of line 241)

The cost of the presumed documentation is that it forces you to de-inline this,
and I'm not sure that's worth it.

+  return static_cast<uint16_t>(bitmap_.size() * 8);
+}
+
 bool NsecRecordRdata::IsEqual(const RecordRdata* other) const {
   if (other->Type() != Type())
     return false;
   const NsecRecordRdata* nsec_other =
       static_cast<const NsecRecordRdata*>(other);
   return bitmap_ == nsec_other->bitmap_;
 }
 
 bool NsecRecordRdata::GetBit(unsigned i) const {
   unsigned byte_num = i/8;
   if (bitmap_.size() < byte_num + 1)
     return false;
 
   unsigned bit_num = 7 - i % 8;
   return (bitmap_[byte_num] & (1 << bit_num)) != 0;
 }
 
 }  // namespace net