Convert remaining StringToLowerASCII to ToLowerASCII

ui/gfx/font_fallback_win.cc

Index: ui/gfx/font_fallback_win.cc
diff --git a/ui/gfx/font_fallback_win.cc b/ui/gfx/font_fallback_win.cc
index e5771cff628f694f2884899d34948aa82a073d98..ecb85aeab9e7a6c947df0fb4ee5b67e9ad14f60e 100644
--- a/ui/gfx/font_fallback_win.cc
+++ b/ui/gfx/font_fallback_win.cc
@@ -29,7 +29,7 @@ void QueryFontsFromRegistry(std::map<std::string, std::string>* map) {
   base::win::RegistryValueIterator it(HKEY_LOCAL_MACHINE, kFonts);
   for (; it.Valid(); ++it) {
     const std::string filename =
-        base::StringToLowerASCII(base::WideToUTF8(it.Value()));
+        base::ToLowerASCII(base::WideToUTF8(it.Value()));
     (*map)[filename] = base::WideToUTF8(it.Name());
   }
 }
@@ -44,7 +44,7 @@ void GetFontNamesFromFilename(const std::string& filename,
     QueryFontsFromRegistry(font_map);
 
   std::map<std::string, std::string>::const_iterator it =
-      font_map->find(base::StringToLowerASCII(filename));
+      font_map->find(base::ToLowerASCII(filename));
   if (it == font_map->end())
     return;