Add use counter for stacked neutral keyframe in CSS Animations

Source/core/animation/css/CSSAnimations.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 47 matching lines @@
 #include "public/platform/Platform.h"
 #include "wtf/BitArray.h"
 #include "wtf/HashSet.h"
 
 namespace blink {
 
 using PropertySet = HashSet<CSSPropertyID>;
 
 namespace {
 
-static PassRefPtrWillBeRawPtr<StringKeyframeEffectModel> createKeyframeEffectModel(StyleResolver* resolver, const Element* animatingElement, Element& element, const ComputedStyle* style, const ComputedStyle* parentStyle, const AtomicString& name, TimingFunction* defaultTimingFunction)
+static PassRefPtrWillBeRawPtr<StringKeyframeEffectModel> createKeyframeEffectModel(StyleResolver* resolver, const Element* animatingElement, Element& element, const ComputedStyle* style, const ComputedStyle* parentStyle, const AtomicString& name, TimingFunction* defaultTimingFunction, size_t animationIndex)
 {
     // When the animating element is null, use its parent for scoping purposes.
     const Element* elementForScoping = animatingElement ? animatingElement : &element;
     const StyleRuleKeyframes* keyframesRule = resolver->findKeyframesRule(elementForScoping, name);
     ASSERT(keyframesRule);
 
     StringKeyframeVector keyframes;
     const WillBeHeapVector<RefPtrWillBeMember<StyleRuleKeyframe>>& styleKeyframes = keyframesRule->keyframes();
 
     // Construct and populate the style for each keyframe
@@ skipping 87 matching lines @@
             bool endNeedsValue = missingEndValues && !endKeyframeProperties.contains(PropertyHandle(property));
             if (!startNeedsValue && !endNeedsValue)
                 continue;
             if (CompositorAnimations::isCompositableProperty(property))
                 UseCounter::count(elementForScoping->document(), UseCounter::SyntheticKeyframesInCompositedCSSAnimation);
         }
     }
 
     RefPtrWillBeRawPtr<StringKeyframeEffectModel> model = StringKeyframeEffectModel::create(keyframes, &keyframes[0]->easing());
     model->forceConversionsToAnimatableValues(element, style);
+    if (animationIndex > 0 && model->hasSyntheticKeyframes())
+        UseCounter::count(elementForScoping->document(), UseCounter::CSSAnimationsStackedNeutralKeyframe);
     return model;
 }
 
 } // namespace
 
 CSSAnimations::CSSAnimations()
 {
 }
 
 bool CSSAnimations::isAnimationForInspector(const Animation& animation)
@@ skipping 68 matching lines @@
                 AnimationMap::const_iterator existing(cssAnimations->m_animations.find(animationName));
                 if (existing != cssAnimations->m_animations.end()) {
                     inactive.remove(animationName);
 
                     const RunningAnimation* runningAnimation = existing->value.get();
                     Animation* animation = runningAnimation->animation.get();
 
                     if (keyframesRule != runningAnimation->styleRule || keyframesRule->version() != runningAnimation->styleRuleVersion || runningAnimation->specifiedTiming != specifiedTiming) {
                         ASSERT(!isAnimationStyleChange);
                         update->updateAnimation(animationName, animation, InertEffect::create(
-                            createKeyframeEffectModel(resolver, animatingElement, element, &style, parentStyle, animationName, keyframeTimingFunction.get()),
+                            createKeyframeEffectModel(resolver, animatingElement, element, &style, parentStyle, animationName, keyframeTimingFunction.get(), i),
                             timing, isPaused, animation->unlimitedCurrentTimeInternal()), specifiedTiming, keyframesRule);
                     } else if (!isAnimationStyleChange && animation->effect() && animation->effect()->isAnimation()) {
                         EffectModel* model = toKeyframeEffect(animation->effect())->model();
                         if (model && model->isKeyframeEffectModel()) {
                             KeyframeEffectModelBase* keyframeEffect = toKeyframeEffectModelBase(model);
                             if (keyframeEffect->hasSyntheticKeyframes())
                                 update->updateAnimationStyle(animation, keyframeEffect, animatingElement->layoutObject(), style);
                         }
                     }
 
                     if (isPaused != animation->paused()) {
                         ASSERT(!isAnimationStyleChange);
                         update->toggleAnimationPaused(animationName);
                     }
 
                     continue;
                 }
             }
 
             ASSERT(!isAnimationStyleChange);
             update->startAnimation(animationName, InertEffect::create(
-                createKeyframeEffectModel(resolver, animatingElement, element, &style, parentStyle, animationName, keyframeTimingFunction.get()),
+                createKeyframeEffectModel(resolver, animatingElement, element, &style, parentStyle, animationName, keyframeTimingFunction.get(), i),
                 timing, isPaused, 0), specifiedTiming, keyframesRule);
         }
     }
 
     ASSERT(inactive.isEmpty() || cssAnimations);
     for (const AtomicString& animationName : inactive) {
         ASSERT(!isAnimationStyleChange);
         update->cancelAnimation(animationName, *cssAnimations->m_animations.get(animationName)->animation);
     }
 }
@@ skipping 508 matching lines @@
     visitor->trace(m_activeInterpolationsForAnimations);
     visitor->trace(m_activeInterpolationsForTransitions);
     visitor->trace(m_newAnimations);
     visitor->trace(m_suppressedAnimations);
     visitor->trace(m_animationsWithUpdates);
     visitor->trace(m_animationsWithStyleUpdates);
 #endif
 }
 
 } // namespace blink