Fix more disabled MSVC warnings, base/ edition.

base/strings/string_number_conversions.cc

 // 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.
 
 #include "base/strings/string_number_conversions.h"
 
 #include <ctype.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <wctype.h>
@@ skipping 85 matching lines @@
 
 // Utility to convert a character to a digit in a given base
 template<typename CHAR, int BASE, bool BASE_LTE_10> class BaseCharToDigit {
 };
 
 // Faster specialization for bases <= 10
 template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, true> {
  public:
   static bool Convert(CHAR c, uint8* digit) {
     if (c >= '0' && c < '0' + BASE) {
-      *digit = c - '0';
+      *digit = static_cast<uint8>(c - '0');
       return true;
     }
     return false;
   }
 };
 
 // Specialization for bases where 10 < base <= 36
 template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, false> {
  public:
   static bool Convert(CHAR c, uint8* digit) {
@@ skipping 403 matching lines @@
 bool HexStringToUInt64(const StringPiece& input, uint64* output) {
   return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
       input.begin(), input.end(), output);
 }
 
 bool HexStringToBytes(const std::string& input, std::vector<uint8>* output) {
   return HexStringToBytesT(input, output);
 }
 
 }  // namespace base