Add AnimationTimingProperties dictionary

Source/core/animation/Animation.idl

Index: Source/core/animation/Animation.idl
diff --git a/Source/core/animation/Animation.idl b/Source/core/animation/Animation.idl
index 02b98bf8234570c35b31e85820a75219fe3f3fa4..a9d194bcd40d14a6c578a577fdf635f4093bddf4 100644
--- a/Source/core/animation/Animation.idl
+++ b/Source/core/animation/Animation.idl
@@ -31,10 +31,9 @@
 // http://dev.w3.org/fxtf/web-animations/#idl-def-Animation
 
 [
-    // FIXME: should be optional union type http://crbug.com/240176
-    Constructor(Element? target, sequence<Dictionary> keyframes),
-    Constructor(Element? target, sequence<Dictionary> keyframes, double timingInput),
-    Constructor(Element? target, sequence<Dictionary> keyframes, Dictionary timingInput),
+    // FIXME: the third argument should be "optional (unrestricted double or AnimationTimingProperties) timing".

[dstockwell, 2015/02/24 03:22:03]

What's still necessary in order to fix this?

[haraken, 2015/02/24 06:11:09]

We don't yet support a dictionary in a union type.

+    Constructor(Element? target, sequence<Dictionary> keyframes, optional unrestricted double timing),
+    Constructor(Element? target, sequence<Dictionary> keyframes, AnimationTimingProperties timing),
     RaisesException=Constructor,
     RuntimeEnabled=WebAnimationsAPI,
 ] interface Animation : AnimationNode {