Throw exception if querying SVGAnimationElement with unresolved interval

Source/core/svg/SVGAnimationElement.idl

 /*
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 15 matching lines @@
 
 // http://www.w3.org/TR/SVG2/animate.html#InterfaceSVGAnimationElement
 
 interface SVGAnimationElement : SVGElement {
     readonly attribute SVGElement targetElement;
 
     attribute EventHandler onbegin;
     attribute EventHandler onend;
     attribute EventHandler onrepeat;
 
-    float getStartTime();
+    [RaisesException] float getStartTime();
     float getCurrentTime();
-    float getSimpleDuration();
+    [RaisesException] float getSimpleDuration();
 
     void beginElement();
     void beginElementAt(float offset);
     void endElement();
     void endElementAt(float offset);
 };
 
 SVGAnimationElement implements SVGTests;