Throw TypeError if easing string is invalid.

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

Index: third_party/WebKit/Source/core/animation/TimingInput.h
diff --git a/third_party/WebKit/Source/core/animation/TimingInput.h b/third_party/WebKit/Source/core/animation/TimingInput.h
index 48f5ed74b18733e777cac2f0c94d0e10457d6863..43ae36657ae011ad00bfb0d08a26f5638a2788db 100644
--- a/third_party/WebKit/Source/core/animation/TimingInput.h
+++ b/third_party/WebKit/Source/core/animation/TimingInput.h
@@ -12,13 +12,14 @@
 namespace blink {
 
 class Dictionary;
+class ExceptionState;
 class KeyframeEffectOptions;
 
 class CORE_EXPORT TimingInput {
     STATIC_ONLY(TimingInput);
 public:
-    static Timing convert(const KeyframeEffectOptions& timingInput);
-    static Timing convert(double duration);
+    static bool convert(const KeyframeEffectOptions& timingInput, Timing& timingOutput, ExceptionState&);
+    static bool convert(double duration, Timing& timingOutput);

[alancutter (OOO until 2018), 2016/04/05 04:50:06]

Why does this need to change? It never returns false.

[suzyh_UTC10 (ex-contributor), 2016/04/12 08:04:23]

It doesn't _need_ to change, but as a user of this API I would expect the two
TimingInput::convert functions to be consistent in this regard.

[alancutter (OOO until 2018), 2016/04/13 00:46:38]

I think it makes the call sites harder to read. It's not clear why we're
asserting that it must succeed until you look into the definition.

[suzyh_UTC10 (ex-contributor), 2016/04/13 01:48:09]

OK, sure. I've put it back the way it was.

 
     static void setStartDelay(Timing&, double startDelay);
     static void setEndDelay(Timing&, double endDelay);
@@ -28,7 +29,7 @@ public:
     static void setIterationDuration(Timing&, double iterationDuration);
     static void setPlaybackRate(Timing&, double playbackRate);
     static void setPlaybackDirection(Timing&, const String& direction);
-    static void setTimingFunction(Timing&, const String& timingFunctionString);
+    static bool setTimingFunction(Timing&, const String& timingFunctionString, ExceptionState&);
 };
 
 } // namespace blink