[WIP] Web Animations API: Constructing an Animation from partial keyframes throws a JS exception

Source/core/animation/EffectInput.cpp

 /*
  * Copyright (C) 2013 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 30 matching lines @@
 namespace WebCore {
 
 static bool checkDocumentAndRenderer(Element* element)
 {
     if (!element->inActiveDocument())
         return false;
     element->document().updateStyleIfNeeded();
     return element->renderer();
 }
 
-PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, const Vector<Dictionary>& keyframeDictionaryVector, bool unsafe)
+PassRefPtrWillBeRawPtr<AnimationEffect> EffectInput::convert(Element* element, const Vector<Dictionary>& keyframeDictionaryVector,  ExceptionState& exceptionState, bool unsafe)
 {
     // FIXME: This test will not be neccessary once resolution of keyframe values occurs at
     // animation application time.
     if (!unsafe && !checkDocumentAndRenderer(element))
         return nullptr;
 
     // FIXME: Move this code into KeyframeEffectModel, it will be used by the IDL constructor for that class.
     KeyframeEffectModel::KeyframeVector keyframes;
     Vector<RefPtr<MutableStylePropertySet> > propertySetVector;
 
@@ skipping 35 matching lines @@
             if (id == CSSPropertyInvalid || !CSSAnimations::isAnimatableProperty(id))
                 continue;
 
             String value;
             keyframeDictionaryVector[i].get(property, value);
             propertySet->setProperty(id, value);
         }
     }
 
     // FIXME: Replace this with code that just parses, when that code is available.
-    return StyleResolver::createKeyframeEffectModel(*element, propertySetVector, keyframes);
+    RefPtrWillBeRawPtr<KeyframeEffectModel> keyframeEffectModel = StyleResolver::createKeyframeEffectModel(*element, propertySetVector, keyframes);
+    if (!keyframeEffectModel->isReplaceOnly())
+        exceptionState.throwDOMException(NotSupportedError, "Partial keyframes are not supported.");
+
+    return keyframeEffectModel;
 }
 
 } // namespace WebCore