Made StyleEngine CSSFontSelectorClient instead of StyleResolver.

Source/core/css/CSSFontSelectorClient.h

 /*
  * Copyright (C) 2014 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * 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 CSSFontSelectorClient_h
 #define CSSFontSelectorClient_h
 
+#include "platform/heap/Handle.h"
+
 namespace WebCore {
 
 class CSSFontSelector;
+class Visitor;
 
 class CSSFontSelectorClient : public NoBaseWillBeGarbageCollectedFinalized<CSSFontSelectorClient> {
 public:
     virtual ~CSSFontSelectorClient() { }
 
     virtual void fontsNeedUpdate(CSSFontSelector*) = 0;
 
     virtual void trace(Visitor*) { }
 };
 
 } // namespace WebCore
 
 #endif // CSSFontSelectorClient_h