Bug 1376594 - Track locally whether an effect is part of an EffectSet to avoid hashmap lookups; r=hiro

MozReview-Commit-ID: IEeAmyR9ZlS

--HG--
extra : rebase_source : 112ec688662a14668839f3ceb45192e50edbe381

dom/animation/KeyframeEffectReadOnly.cpp

@@ -957,12 +957,13 @@ KeyframeEffectReadOnly::UpdateTargetRegistration()
   MOZ_ASSERT(isRelevant == IsCurrent() || IsInEffect(),
              "Out of date Animation::IsRelevant value");
 
-  if (isRelevant) {
+  if (isRelevant && !mInEffectSet) {
     EffectSet* effectSet =
       EffectSet::GetOrCreateEffectSet(mTarget->mElement, mTarget->mPseudoType);
     effectSet->AddEffect(*this);
+    mInEffectSet = true;
     UpdateEffectSet(effectSet);
-  } else {
+  } else if (!isRelevant && mInEffectSet) {
     UnregisterTarget();
   }
 }
@@ -970,8 +971,15 @@ KeyframeEffectReadOnly::UpdateTargetRegistration()
 void
 KeyframeEffectReadOnly::UnregisterTarget()
 {
+  if (!mInEffectSet) {
+    return;
+  }
+
   EffectSet* effectSet =
     EffectSet::GetEffectSet(mTarget->mElement, mTarget->mPseudoType);
+  MOZ_ASSERT(effectSet, "If mInEffectSet is true, there must be an EffectSet"
+                        " on the target element");
+  mInEffectSet = false;
   if (effectSet) {
     effectSet->RemoveEffect(*this);
 
@@ -1834,6 +1842,10 @@ KeyframeEffectReadOnly::ContainsAnimatedScale(const nsIFrame* aFrame) const
 void
 KeyframeEffectReadOnly::UpdateEffectSet(EffectSet* aEffectSet) const
 {
+  if (!mInEffectSet) {
+    return;
+  }
+
   EffectSet* effectSet =
     aEffectSet ? aEffectSet
                : EffectSet::GetEffectSet(mTarget->mElement,

dom/animation/KeyframeEffectReadOnly.h

@@ -417,6 +417,11 @@ protected:
   nsRefPtrHashtable<nsUint32HashKey, RawServoAnimationValue>
     mBaseStyleValuesForServo;
 
+  // True if this effect is in the EffectSet for its target element. This is
+  // used as an optimization to avoid unnecessary hashmap lookups on the
+  // EffectSet.
+  bool mInEffectSet = false;
+
   // We only want to record telemetry data for "ContentTooLarge" warnings once
   // per effect:target pair so we use this member to record if we have already
   // reported a "ContentTooLarge" warning for the current target.