Clean up creation of "detached" SVG* data type objects

third_party/WebKit/Source/core/svg/SVGNumberTearOff.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 24 matching lines @@
 #include "core/svg/properties/SVGPropertyTearOff.h"
 #include "platform/bindings/ScriptWrappable.h"
 
 namespace blink {
 
 class SVGNumberTearOff : public SVGPropertyTearOff<SVGNumber>,
                          public ScriptWrappable {
   DEFINE_WRAPPERTYPEINFO();
 
  public:
-  static SVGNumberTearOff* Create(
-      SVGNumber* target,
-      SVGElement* context_element,
-      PropertyIsAnimValType property_is_anim_val,
-      const QualifiedName& attribute_name = QualifiedName::Null()) {
+  static SVGNumberTearOff* Create(SVGNumber* target,
+                                  SVGElement* context_element,
+                                  PropertyIsAnimValType property_is_anim_val,
+                                  const QualifiedName& attribute_name) {
     return new SVGNumberTearOff(target, context_element, property_is_anim_val,
                                 attribute_name);
   }
+  static SVGNumberTearOff* CreateDetached();
 
   DECLARE_VIRTUAL_TRACE_WRAPPERS();
 
   void setValue(float, ExceptionState&);
   float value() { return Target()->Value(); }
 
  protected:
   SVGNumberTearOff(SVGNumber*,
                    SVGElement* context_element,
                    PropertyIsAnimValType,
-                   const QualifiedName& attribute_name = QualifiedName::Null());
+                   const QualifiedName& attribute_name);
 };
 
 }  // namespace blink
 
 #endif  // SVGNumberTearOff_h