Make FontListImpl RefCountedThreadSafe

ui/gfx/platform_font.h

 // 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.
 
 #ifndef UI_GFX_PLATFORM_FONT_H_
 #define UI_GFX_PLATFORM_FONT_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 
 class Font;
 struct FontRenderParams;
 
-class GFX_EXPORT PlatformFont : public base::RefCounted<PlatformFont> {
+class GFX_EXPORT PlatformFont
+    : public base::RefCountedThreadSafe<PlatformFont> {
  public:
   // Creates an appropriate PlatformFont implementation.
   static PlatformFont* CreateDefault();
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
   static PlatformFont* CreateFromNativeFont(NativeFont native_font);
 #endif
   // Creates a PlatformFont implementation with the specified |font_name|
   // (encoded in UTF-8) and |font_size| in pixels.
   static PlatformFont* CreateFromNameAndSize(const std::string& font_name,
                                              int font_size);
@@ skipping 45 matching lines @@
 
 #if defined(OS_WIN) || defined(OS_MACOSX) || defined(OS_IOS)
   // Returns the native font handle.
   virtual NativeFont GetNativeFont() const = 0;
 #endif
 
  protected:
   virtual ~PlatformFont() {}
 
  private:
-  friend class base::RefCounted<PlatformFont>;
+  friend class base::RefCountedThreadSafe<PlatformFont>;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_PLATFORM_FONT_H_