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 12dc5c710500da09db06ffb1a5b4673ab994170e..5687d25b7db901b996d5390cfb08139ac5df4a79 100644
--- a/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/CSSToStyleMap.cpp
@@ -459,6 +459,13 @@ PassRefPtr<TimingFunction> CSSToStyleMap::MapAnimationTimingFunction(
   if (value.IsInitialValue())
     return CSSTimingData::InitialTimingFunction();
 
+  if (value.IsFramesTimingFunctionValue()) {
+    const CSSFramesTimingFunctionValue& frames_timing_function =
+        ToCSSFramesTimingFunctionValue(value);
+    return FramesTimingFunction::Create(
+        frames_timing_function.NumberOfFrames());
+  }
+
   const CSSStepsTimingFunctionValue& steps_timing_function =
       ToCSSStepsTimingFunctionValue(value);
   if (steps_timing_function.GetStepPosition() ==