Throw TypeError if easing string is invalid.

third_party/WebKit/Source/core/animation/ElementAnimation.h

Index: third_party/WebKit/Source/core/animation/ElementAnimation.h
diff --git a/third_party/WebKit/Source/core/animation/ElementAnimation.h b/third_party/WebKit/Source/core/animation/ElementAnimation.h
index eda33d96b1dd86063ee391ef8626c310be1e4293..874e0078dda498ce1538d443906185dff0ce9b29 100644
--- a/third_party/WebKit/Source/core/animation/ElementAnimation.h
+++ b/third_party/WebKit/Source/core/animation/ElementAnimation.h
@@ -55,16 +55,21 @@ public:
         EffectModel* effect = EffectInput::convert(&element, effectInput, executionContext, exceptionState);
         if (exceptionState.hadException())
             return 0;
-        return animateInternal(element, effect, TimingInput::convert(duration));
+        Timing timing;
+        bool success = TimingInput::convert(duration, timing);
+        DCHECK(success);
+        return animateInternal(element, effect, timing);
     }
 
     static Animation* animate(ExecutionContext* executionContext, Element& element, const EffectModelOrDictionarySequenceOrDictionary& effectInput, const KeyframeEffectOptions& options, ExceptionState& exceptionState)
     {
         EffectModel* effect = EffectInput::convert(&element, effectInput, executionContext, exceptionState);
-        if (exceptionState.hadException())
+        Timing timing;
+        bool success = TimingInput::convert(options, timing, &element.document(), exceptionState);
+        if (!success || exceptionState.hadException())
             return 0;
 
-        Animation* animation = animateInternal(element, effect, TimingInput::convert(options, &element.document()));
+        Animation* animation = animateInternal(element, effect, timing);
         animation->setId(options.id());
         return animation;
     }