Trim FontSelector interface a bit.

Source/platform/fonts/FontSelector.h

 /*
  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef FontSelector_h
 #define FontSelector_h
 
+#include "platform/fonts/FontCacheClient.h"
 #include "wtf/Forward.h"
 #include "wtf/PassRefPtr.h"
-#include "wtf/RefCounted.h"
 
 namespace WebCore {
 
 class FontData;
 class FontDescription;
-class FontSelectorClient;
 
-class FontSelector : public RefCounted<FontSelector> {
+class FontSelector : public FontCacheClient {
 public:
     virtual ~FontSelector() { }
     virtual PassRefPtr<FontData> getFontData(const FontDescription&, const AtomicString& familyName) = 0;
     virtual void willUseFontData(const FontDescription&, const AtomicString& familyName) = 0;
 
-    virtual void fontCacheInvalidated() { }
-
-    virtual void registerForInvalidationCallbacks(FontSelectorClient*) = 0;
-    virtual void unregisterForInvalidationCallbacks(FontSelectorClient*) = 0;
-
     virtual unsigned version() const = 0;
 };
 
-class FontSelectorClient {
-public:
-    virtual ~FontSelectorClient() { }
-
-    virtual void fontsNeedUpdate(FontSelector*) = 0;
-};
-
 } // namespace WebCore
 
 #endif // FontSelector_h