Add use counters for function values of easing

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

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/animation/AnimationEffectTiming.h"
 
 #include "bindings/core/v8/UnionTypesCore.h"
 #include "core/animation/AnimationEffect.h"
 #include "core/animation/KeyframeEffect.h"
 #include "platform/animation/TimingFunction.h"
@@ skipping 112 matching lines @@
 void AnimationEffectTiming::setDirection(String direction)
 {
     Timing timing = m_parent->specifiedTiming();
     TimingInput::setPlaybackDirection(timing, direction);
     m_parent->updateSpecifiedTiming(timing);
 }
 
 void AnimationEffectTiming::setEasing(String easing)
 {
     Timing timing = m_parent->specifiedTiming();
-    TimingInput::setTimingFunction(timing, easing);
+    TimingInput::setTimingFunction(timing, easing, nullptr);

[alancutter (OOO until 2018), 2016/04/07 07:36:20]

I would add a TODO here to add [SetterCallWith=Document] to IDL or a comment
explaining why it's okay to not use count this scenario.

     m_parent->updateSpecifiedTiming(timing);
 }
 
 DEFINE_TRACE(AnimationEffectTiming)
 {
     visitor->trace(m_parent);
 }
 
 } // namespace blink