Replace ToLower calls to the new format

chrome/browser/extensions/api/file_system/file_system_api.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 "chrome/browser/extensions/api/file_system/file_system_api.h"
 
 #include <set>
 #include <vector>
 
 #include "apps/saved_files_service.h"
@@ skipping 133 matching lines @@
     base::string16* description) {
   std::set<base::FilePath::StringType> extension_set;
   int description_id = 0;
 
   if (accept_option.mime_types.get()) {
     std::vector<std::string>* list = accept_option.mime_types.get();
     bool valid_type = false;
     for (std::vector<std::string>::const_iterator iter = list->begin();
          iter != list->end(); ++iter) {
       std::vector<base::FilePath::StringType> inner;
-      std::string accept_type = *iter;
-      base::StringToLowerASCII(&accept_type);
+      std::string accept_type = base::ToLowerASCII(*iter);
       net::GetExtensionsForMimeType(accept_type, &inner);
       if (inner.empty())
         continue;
 
       if (valid_type)
         description_id = 0;  // We already have an accept type with label; if
                              // we find another, give up and use the default.
       else if (accept_type == "image/*")
         description_id = IDS_IMAGE_FILES;
       else if (accept_type == "audio/*")
         description_id = IDS_AUDIO_FILES;
       else if (accept_type == "video/*")
         description_id = IDS_VIDEO_FILES;
 
       extension_set.insert(inner.begin(), inner.end());
       valid_type = true;
     }
   }
 
   if (accept_option.extensions.get()) {
     std::vector<std::string>* list = accept_option.extensions.get();
     for (std::vector<std::string>::const_iterator iter = list->begin();
          iter != list->end(); ++iter) {
-      std::string extension = *iter;
-      base::StringToLowerASCII(&extension);
+      std::string extension = base::ToLowerASCII(*iter);
 #if defined(OS_WIN)
       extension_set.insert(base::UTF8ToWide(*iter));
 #else
       extension_set.insert(*iter);
 #endif
     }
   }
 
   extensions->assign(extension_set.begin(), extension_set.end());
   if (extensions->empty())
@@ skipping 1251 matching lines @@
   std::vector<linked_ptr<Volume>> result_volume_list;
   FillVolumeList(chrome_details_.GetProfile(), &result_volume_list);
 
   return RespondNow(
       ArgumentList(api::file_system::GetVolumeList::Results::Create(
                        result_volume_list).Pass()));
 }
 #endif
 
 }  // namespace extensions