Trim FontSelector interface a bit.

Source/platform/fonts/FontCacheClient.h

Index: Source/platform/fonts/FontCacheClient.h
diff --git a/Source/core/svg/SVGAnimatedLengthList.h b/Source/platform/fonts/FontCacheClient.h
similarity index 83%
copy from Source/core/svg/SVGAnimatedLengthList.h
copy to Source/platform/fonts/FontCacheClient.h
index 8b4f5f11713fd7671bb238493dd7462510445e5b..4e43b8c72cf93e9d6f51f68098d434a9d97444ce 100644
--- a/Source/core/svg/SVGAnimatedLengthList.h
+++ b/Source/platform/fonts/FontCacheClient.h
@@ -28,16 +28,21 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef SVGAnimatedLengthList_h
-#define SVGAnimatedLengthList_h
+#ifndef FontCacheClient_h
+#define FontCacheClient_h
 
-#include "core/svg/SVGLengthListTearOff.h"
-#include "core/svg/properties/NewSVGAnimatedProperty.h"
+#include "platform/PlatformExport.h"
+#include "wtf/RefCounted.h"
 
 namespace WebCore {
 
-typedef NewSVGAnimatedProperty<SVGLengthList> SVGAnimatedLengthList;
+class PLATFORM_EXPORT FontCacheClient : public RefCounted<FontCacheClient> {
+public:
+    virtual ~FontCacheClient() { }
+
+    virtual void fontCacheInvalidated() = 0;
+};
 
 } // namespace WebCore
 
-#endif
+#endif // FontCacheClient_h