Deprecate step timing with position 'middle'

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 2871b80e03e2a941a2ec40771db795812ce19d13..7206405da42a9e23a6d7f8b0dde9c8f232d201df 100644
--- a/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
+++ b/third_party/WebKit/Source/core/animation/AnimationInputHelpers.cpp
@@ -254,7 +254,8 @@ PassRefPtr<TimingFunction> AnimationInputHelpers::ParseTimingFunction(
     exception_state.ThrowTypeError("Easing may not be set to a list of values");
     return nullptr;
   }
-  return CSSToStyleMap::MapAnimationTimingFunction(value_list->Item(0), true);
+  return CSSToStyleMap::MapAnimationTimingFunction(value_list->Item(0), true,
+                                                   document);
 }
 
 }  // namespace blink