Discard SampledEffects on elements if they are redundant

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

Index: third_party/WebKit/Source/core/animation/SampledEffect.cpp
diff --git a/third_party/WebKit/Source/core/animation/SampledEffect.cpp b/third_party/WebKit/Source/core/animation/SampledEffect.cpp
index 30aee7ab143d913f88ab898e5b86e384e2d22815..bad5be900f7b94aefacc5fa42d5d77d87c30c2a6 100644
--- a/third_party/WebKit/Source/core/animation/SampledEffect.cpp
+++ b/third_party/WebKit/Source/core/animation/SampledEffect.cpp
@@ -8,7 +8,6 @@ namespace blink {
 
 SampledEffect::SampledEffect(KeyframeEffect* effect)
     : m_effect(effect)
-    , m_animation(effect->animation())
     , m_sequenceNumber(effect->animation()->sequenceNumber())
     , m_priority(effect->priority())
 {
@@ -17,14 +16,35 @@ SampledEffect::SampledEffect(KeyframeEffect* effect)
 void SampledEffect::clear()
 {
     m_effect = nullptr;
-    m_animation = nullptr;
     m_interpolations.clear();
 }
 
+bool SampledEffect::willNeverChange() const
+{
+    return !m_effect || !m_effect->animation();
+}
+
+void SampledEffect::removeReplacedInterpolations(const HashSet<PropertyHandle>& replacedProperties)
+{
+    size_t newSize = 0;
+    for (auto& interpolation : m_interpolations) {
+        if (!replacedProperties.contains(interpolation->property()))
+            m_interpolations[newSize++].swap(interpolation);
+    }
+    m_interpolations.shrink(newSize);
+}
+
+void SampledEffect::updateReplacedProperties(HashSet<PropertyHandle>& replacedProperties)
+{
+    for (const auto& interpolation : m_interpolations) {
+        if (!interpolation->dependsOnUnderlyingValue())
+            replacedProperties.add(interpolation->property());
+    }
+}
+
 DEFINE_TRACE(SampledEffect)
 {
     visitor->trace(m_effect);
-    visitor->trace(m_animation);
 }
 
 } // namespace blink