Decouple FileSystem and WebSQL callbacks from VoidCallback and it non-refcounted

Source/modules/filesystem/FileSystemVoidCallback.h

Index: Source/modules/filesystem/FileSystemVoidCallback.h
diff --git a/Source/core/html/VoidCallback.h b/Source/modules/filesystem/FileSystemVoidCallback.h
similarity index 89%
copy from Source/core/html/VoidCallback.h
copy to Source/modules/filesystem/FileSystemVoidCallback.h
index 0c3688097eefc8939f2dc5c53e907dd22c7d2709..240aeb6ce10df2163381adf3e65438704b72e9c3 100644
--- a/Source/core/html/VoidCallback.h
+++ b/Source/modules/filesystem/FileSystemVoidCallback.h
@@ -23,16 +23,16 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef VoidCallback_h
-#define VoidCallback_h
+#ifndef FileSystemVoidCallback_h
+#define FileSystemVoidCallback_h
 
 #include "wtf/RefCounted.h"
 
 namespace WebCore {
 
-class VoidCallback : public RefCounted<VoidCallback> {
+class FileSystemVoidCallback : public RefCounted<FileSystemVoidCallback> {
 public:
-    virtual ~VoidCallback() { }
+    virtual ~FileSystemVoidCallback() { }
     virtual bool handleEvent() = 0;
 };