Make IDL Callbacks non-refcounted by default

Source/modules/quota/StorageUsageCallback.h

 /*
  * Copyright (C) 2011 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 StorageUsageCallback_h
 #define StorageUsageCallback_h
 
-#include "wtf/RefCounted.h"
-
 namespace WebCore {
 
-class StorageUsageCallback : public RefCounted<StorageUsageCallback> {
+class StorageUsageCallback {
 public:
     virtual ~StorageUsageCallback() { }
     virtual bool handleEvent(unsigned long long currentUsageInBytes, unsigned long long currentQuotaInBytes) = 0;
 };
 
 } // namespace
 
 #endif // StorageUsageCallback_h