Move StringToLowerASCII to base namespace

chrome/browser/extensions/api/file_system/file_system_api.cc

Index: chrome/browser/extensions/api/file_system/file_system_api.cc
diff --git a/chrome/browser/extensions/api/file_system/file_system_api.cc b/chrome/browser/extensions/api/file_system/file_system_api.cc
index 2e842b5be477485c02e9324af806925da6193d76..5a6772e72380a790d0c59fc45956fa36ddd7e70c 100644
--- a/chrome/browser/extensions/api/file_system/file_system_api.cc
+++ b/chrome/browser/extensions/api/file_system/file_system_api.cc
@@ -102,7 +102,7 @@ bool GetFileTypesFromAcceptOption(
          iter != list->end(); ++iter) {
       std::vector<base::FilePath::StringType> inner;
       std::string accept_type = *iter;
-      StringToLowerASCII(&accept_type);
+      base::StringToLowerASCII(&accept_type);
       net::GetExtensionsForMimeType(accept_type, &inner);
       if (inner.empty())
         continue;
@@ -127,7 +127,7 @@ bool GetFileTypesFromAcceptOption(
     for (std::vector<std::string>::const_iterator iter = list->begin();
          iter != list->end(); ++iter) {
       std::string extension = *iter;
-      StringToLowerASCII(&extension);
+      base::StringToLowerASCII(&extension);
 #if defined(OS_WIN)
       extension_set.insert(base::UTF8ToWide(*iter));
 #else