Web Animations: Allow animations with delay to start on compositor

LayoutTests/compositing/layer-creation/animation-overlap-with-children.html

Index: LayoutTests/compositing/layer-creation/animation-overlap-with-children.html
diff --git a/LayoutTests/compositing/layer-creation/animation-overlap-with-children.html b/LayoutTests/compositing/layer-creation/animation-overlap-with-children.html
index 6289c6b7dd3943ed4c81d17ee85a81165d801e51..bb489867ca6d64e67e20af68d18cd78ff8f1005d 100644
--- a/LayoutTests/compositing/layer-creation/animation-overlap-with-children.html
+++ b/LayoutTests/compositing/layer-creation/animation-overlap-with-children.html
@@ -48,7 +48,7 @@
     }
     
     @-webkit-keyframes slide {
-      from { -webkit-transform: none; }
+      from { -webkit-transform: translateX(0px); }

[Julien - ping for review, 2014/03/10 18:11:59]

Could you explain what the rationale for the test changes are?

[dstockwell, 2014/03/11 03:21:30]

Previously an interpolation from none -> translate would produce the identity
transform at time 0, now we produce 'none'. Added to description.

       to { -webkit-transform: translateX(100px); }
     }
   </style>