Implement frames() timing function

third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp

Index: third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp b/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
index d6fb1f6a3b19e74fa60a938368299c0dcb0d9a46..2b09d81c79e227fd8496bb5e116aad1f9501b555 100644
--- a/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
@@ -458,6 +458,12 @@ PassRefPtr<TimingFunction> CSSToStyleMap::mapAnimationTimingFunction(
   if (value.isInitialValue())
     return CSSTimingData::initialTimingFunction();
 
+  if (value.isFramesTimingFunctionValue()) {
+    const CSSFramesTimingFunctionValue& framesTimingFunction =
+        toCSSFramesTimingFunctionValue(value);
+    return FramesTimingFunction::create(framesTimingFunction.numberOfFrames());
+  }
+
   const CSSStepsTimingFunctionValue& stepsTimingFunction =
       toCSSStepsTimingFunctionValue(value);
   if (stepsTimingFunction.getStepPosition() ==