Make FontListImpl RefCountedThreadSafe

ui/gfx/font_list_impl.h

Index: ui/gfx/font_list_impl.h
diff --git a/ui/gfx/font_list_impl.h b/ui/gfx/font_list_impl.h
index d405288195c7802a24f31c6723a0ffb50e6c1002..ef3fb8447b5c97e397575d5cd1f7b0950542d458 100644
--- a/ui/gfx/font_list_impl.h
+++ b/ui/gfx/font_list_impl.h
@@ -25,7 +25,7 @@ namespace gfx {
 // other form.
 //
 // For the format of font description string, see font_list.h for details.
-class FontListImpl : public base::RefCounted<FontListImpl> {
+class FontListImpl : public base::RefCountedThreadSafe<FontListImpl> {
  public:
   // Creates a font list from a string representing font names, styles, and
   // size.
@@ -85,7 +85,7 @@ class FontListImpl : public base::RefCounted<FontListImpl> {
   const Font& GetPrimaryFont() const;
 
  private:
-  friend class base::RefCounted<FontListImpl>;
+  friend class base::RefCountedThreadSafe<FontListImpl>;
 
   ~FontListImpl();