Avoid a copy in the debug check in GetStringFUTF16().

ui/base/l10n/l10n_util.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 "ui/base/l10n/l10n_util.h"
 
 #include <algorithm>
 #include <cstdlib>
 #include <iterator>
 #include <memory>
@@ skipping 681 matching lines @@
   // practice, the strings should be relatively short.
   ResourceBundle& rb = ResourceBundle::GetSharedInstance();
   const base::string16& format_string = rb.GetLocalizedString(message_id);
 
 #ifndef NDEBUG
   // Make sure every replacement string is being used, so we don't just
   // silently fail to insert one. If |offsets| is non-NULL, then don't do this
   // check as the code may simply want to find the placeholders rather than
   // actually replacing them.
   if (!offsets) {
-    std::string utf8_string = base::UTF16ToUTF8(format_string);
-
     // $9 is the highest allowed placeholder.
     for (size_t i = 0; i < 9; ++i) {
       bool placeholder_should_exist = replacements.size() > i;
 
-      std::string placeholder =
-          base::StringPrintf("$%d", static_cast<int>(i + 1));
-      size_t pos = utf8_string.find(placeholder.c_str());
+      base::string16 placeholder = base::ASCIIToUTF16("$");
+      placeholder += (L'1' + i);

[Lei Zhang, 2016/05/25 00:07:02]

At least Linux didn't like having this as part of the previous line.

[jungshik at Google, 2016/05/25 07:37:05]

|L'1'| is wchar_t (32-bit) on Linux/Mac. Didn't you get any warning from
compilers? 

[jungshik at Google, 2016/05/25 08:26:34]

oh. trybots all come back green. 

+      size_t pos = format_string.find(placeholder);
       if (placeholder_should_exist) {
-        DCHECK_NE(std::string::npos, pos) <<
-            " Didn't find a " << placeholder << " placeholder in " <<
-            utf8_string;
+        DCHECK_NE(std::string::npos, pos) << " Didn't find a " << placeholder

[Lei Zhang, 2016/05/25 00:07:02]

This is just "git cl format" lining things up.

+                                          << " placeholder in "
+                                          << format_string;
       } else {
-        DCHECK_EQ(std::string::npos, pos) <<
-            " Unexpectedly found a " << placeholder << " placeholder in " <<
-            utf8_string;
+        DCHECK_EQ(std::string::npos, pos) << " Unexpectedly found a "
+                                          << placeholder << " placeholder in "
+                                          << format_string;
       }
     }
   }
 #endif
 
   base::string16 formatted = base::ReplaceStringPlaceholders(
       format_string, replacements, offsets);
   AdjustParagraphDirectionality(&formatted);
 
   return formatted;
@@ skipping 129 matching lines @@
 }
 
 const std::vector<std::string>& GetAvailableLocales() {
   return g_available_locales.Get();
 }
 
 void GetAcceptLanguagesForLocale(const std::string& display_locale,
                                  std::vector<std::string>* locale_codes) {
   for (size_t i = 0; i < arraysize(kAcceptLanguageList); ++i) {
     if (!l10n_util::IsLocaleNameTranslated(kAcceptLanguageList[i],
-                                           display_locale))
-      // TODO(jungshik) : Put them at the of the list with language codes
+                                           display_locale)) {
+      // TODO(jungshik) : Put them at the end of the list with language codes

[Lei Zhang, 2016/05/25 00:07:03]

I think that's what you meant to say?

       // enclosed by brackets instead of skipping.
-        continue;
+      continue;
+    }
     locale_codes->push_back(kAcceptLanguageList[i]);
   }
 }
 
 int GetLocalizedContentsWidthInPixels(int pixel_resource_id) {
   int width = 0;
   base::StringToInt(l10n_util::GetStringUTF8(pixel_resource_id), &width);
   DCHECK_GT(width, 0);
   return width;
 }
 
 const char* const* GetAcceptLanguageListForTesting() {
   return kAcceptLanguageList;
 }
 
 size_t GetAcceptLanguageListSizeForTesting() {
   return arraysize(kAcceptLanguageList);
 }
 
 }  // namespace l10n_util