Pull in ASCII<->UTF16 from Chromium

base/strings/utf_string_conversions.cc

 // Copyright 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_conversions.h"
 
 #include <stdint.h>
 
 #include <string>
 
+#include "base/logging.h"
 #include "base/strings/string16.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversion_utils.h"
 
 namespace {
 
 template<typename SRC_CHAR, typename DEST_STRING>
 bool ConvertUnicode(const SRC_CHAR* src,
                     size_t src_len,
                     DEST_STRING* output) {
   bool success = true;
   int32_t src_len32 = static_cast<int32_t>(src_len);
@@ skipping 29 matching lines @@
   base::PrepareForUTF8Output(src, src_len, output);
   return ConvertUnicode(src, src_len, output);
 }
 
 std::string UTF16ToUTF8(const string16& utf16) {
   std::string ret;
   UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
   return ret;
 }
 
+string16 ASCIIToUTF16(const StringPiece& ascii) {
+  DCHECK(IsStringASCII(ascii)) << ascii;
+  return string16(ascii.begin(), ascii.end());
+}
+
+std::string UTF16ToASCII(const string16& utf16) {
+  DCHECK(IsStringASCII(utf16)) << UTF16ToUTF8(utf16);
+  return std::string(utf16.begin(), utf16.end());
+}
 }  // namespace