Web Animations: support cssOffset

third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp

Index: third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
diff --git a/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp b/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
index 5a0a86cc6e16add044e87fbcb94abdc15bd38d8e..d3a9dca9113375919d44f0f16768e32d334db383 100644
--- a/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
+++ b/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
@@ -42,6 +42,8 @@ CSSPropertyID AnimationInputHelpers::keyframeAttributeToCSSProperty(
     return CSSPropertyInvalid;
   if (property == "cssFloat")
     return CSSPropertyFloat;
+  if (property == "cssOffset")
+    return CSSPropertyOffset;
 
   StringBuilder builder;
   for (size_t i = 0; i < property.length(); ++i) {