Fix more disabled MSVC warnings, base/ edition.

base/strings/utf_string_conversion_utils.cc

 // Copyright (c) 2009 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/utf_string_conversion_utils.h"
 
 #include "base/third_party/icu/icu_utf.h"
 
 namespace base {
 
@@ skipping 53 matching lines @@
   // Validate the value.
   return IsValidCodepoint(*code_point);
 }
 #endif  // defined(WCHAR_T_IS_UTF32)
 
 // WriteUnicodeCharacter -------------------------------------------------------
 
 size_t WriteUnicodeCharacter(uint32 code_point, std::string* output) {
   if (code_point <= 0x7f) {
     // Fast path the common case of one byte.
-    output->push_back(code_point);
+    output->push_back(static_cast<char>(code_point));
     return 1;
   }
 
 
   // CBU8_APPEND_UNSAFE can append up to 4 bytes.
   size_t char_offset = output->length();
   size_t original_char_offset = char_offset;
   output->resize(char_offset + CBU8_MAX_LENGTH);
 
   CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
@@ skipping 54 matching lines @@
     // character.
     output->reserve(src_len / 2);
   }
 }
 
 // Instantiate versions we know callers will need.
 template void PrepareForUTF16Or32Output(const char*, size_t, std::wstring*);
 template void PrepareForUTF16Or32Output(const char*, size_t, string16*);
 
 }  // namespace base