1 files changed, 969 insertions, 0 deletions
diff --git a/dom/animation/EffectCompositor.cpp b/dom/animation/EffectCompositor.cpp
new file mode 100644
index 0000000000..095ec63baf
--- /dev/null
+++ b/dom/animation/EffectCompositor.cpp
@@ -0,0 +1,969 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "EffectCompositor.h"
+
+#include <bitset>
+#include <initializer_list>
+
+#include "mozilla/dom/Animation.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/KeyframeEffect.h"
+#include "mozilla/AnimationComparator.h"
+#include "mozilla/AnimationPerformanceWarning.h"
+#include "mozilla/AnimationTarget.h"
+#include "mozilla/AnimationUtils.h"
+#include "mozilla/AutoRestore.h"
+#include "mozilla/ComputedStyleInlines.h"
+#include "mozilla/EffectSet.h"
+#include "mozilla/LayerAnimationInfo.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/PresShellInlines.h"
+#include "mozilla/RestyleManager.h"
+#include "mozilla/ServoBindings.h"  // Servo_GetProperties_Overriding_Animation
+#include "mozilla/ServoStyleSet.h"
+#include "mozilla/StaticPrefs_layers.h"
+#include "mozilla/StyleAnimationValue.h"
+#include "nsContentUtils.h"
+#include "nsCSSPseudoElements.h"
+#include "nsCSSPropertyIDSet.h"
+#include "nsCSSProps.h"
+#include "nsDisplayItemTypes.h"
+#include "nsAtom.h"
+#include "nsLayoutUtils.h"
+#include "nsTArray.h"
+#include "PendingAnimationTracker.h"
+
+using mozilla::dom::Animation;
+using mozilla::dom::Element;
+using mozilla::dom::KeyframeEffect;
+
+namespace mozilla {
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(EffectCompositor)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(EffectCompositor)
+  for (auto& elementSet : tmp->mElementsToRestyle) {
+    elementSet.Clear();
+  }
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(EffectCompositor)
+  for (const auto& elementSet : tmp->mElementsToRestyle) {
+    for (const auto& key : elementSet.Keys()) {
+      CycleCollectionNoteChild(cb, key.mElement,
+                               "EffectCompositor::mElementsToRestyle[]",
+                               cb.Flags());
+    }
+  }
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+/* static */
+bool EffectCompositor::AllowCompositorAnimationsOnFrame(
+    const nsIFrame* aFrame,
+    AnimationPerformanceWarning::Type& aWarning /* out */) {
+  if (aFrame->RefusedAsyncAnimation()) {
+    return false;
+  }
+
+  if (!nsLayoutUtils::AreAsyncAnimationsEnabled()) {
+    if (StaticPrefs::layers_offmainthreadcomposition_log_animations()) {
+      nsCString message;
+      message.AppendLiteral(
+          "Performance warning: Async animations are "
+          "disabled");
+      AnimationUtils::LogAsyncAnimationFailure(message);
+    }
+    return false;
+  }
+
+  // Disable async animations if we have a rendering observer that
+  // depends on our content (svg masking, -moz-element etc) so that
+  // it gets updated correctly.
+  nsIContent* content = aFrame->GetContent();
+  while (content) {
+    if (content->HasRenderingObservers()) {
+      aWarning = AnimationPerformanceWarning::Type::HasRenderingObserver;
+      return false;
+    }
+    content = content->GetParent();
+  }
+
+  return true;
+}
+
+// Helper function to factor out the common logic from
+// GetAnimationsForCompositor and HasAnimationsForCompositor.
+//
+// Takes an optional array to fill with eligible animations.
+//
+// Returns true if there are eligible animations, false otherwise.
+bool FindAnimationsForCompositor(
+    const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet,
+    nsTArray<RefPtr<dom::Animation>>* aMatches /*out*/) {
+  // Do not process any animations on the compositor when in print or print
+  // preview.
+  if (aFrame->PresContext()->IsPrintingOrPrintPreview()) {
+    return false;
+  }
+
+  MOZ_ASSERT(
+      aPropertySet.IsSubsetOf(LayerAnimationInfo::GetCSSPropertiesFor(
+          DisplayItemType::TYPE_TRANSFORM)) ||
+          aPropertySet.IsSubsetOf(LayerAnimationInfo::GetCSSPropertiesFor(
+              DisplayItemType::TYPE_OPACITY)) ||
+          aPropertySet.IsSubsetOf(LayerAnimationInfo::GetCSSPropertiesFor(
+              DisplayItemType::TYPE_BACKGROUND_COLOR)),
+      "Should be the subset of transform-like properties, or opacity, "
+      "or background color");
+
+  MOZ_ASSERT(!aMatches || aMatches->IsEmpty(),
+             "Matches array, if provided, should be empty");
+
+  EffectSet* effects = EffectSet::GetForFrame(aFrame, aPropertySet);
+  if (!effects || effects->IsEmpty()) {
+    return false;
+  }
+
+  // First check for newly-started transform animations that should be
+  // synchronized with geometric animations. We need to do this before any
+  // other early returns (the one above is ok) since we can only check this
+  // state when the animation is newly-started.
+  if (aPropertySet.Intersects(LayerAnimationInfo::GetCSSPropertiesFor(
+          DisplayItemType::TYPE_TRANSFORM))) {
+    PendingAnimationTracker* tracker =
+        aFrame->PresContext()->Document()->GetPendingAnimationTracker();
+    if (tracker) {
+      tracker->MarkAnimationsThatMightNeedSynchronization();
+    }
+  }
+
+  AnimationPerformanceWarning::Type warning =
+      AnimationPerformanceWarning::Type::None;
+  if (!EffectCompositor::AllowCompositorAnimationsOnFrame(aFrame, warning)) {
+    if (warning != AnimationPerformanceWarning::Type::None) {
+      EffectCompositor::SetPerformanceWarning(
+          aFrame, aPropertySet, AnimationPerformanceWarning(warning));
+    }
+    return false;
+  }
+
+  // The animation cascade will almost always be up-to-date by this point
+  // but there are some cases such as when we are restoring the refresh driver
+  // from test control after seeking where it might not be the case.
+  //
+  // Those cases are probably not important but just to be safe, let's make
+  // sure the cascade is up to date since if it *is* up to date, this is
+  // basically a no-op.
+  Maybe<NonOwningAnimationTarget> pseudoElement =
+      EffectCompositor::GetAnimationElementAndPseudoForFrame(
+          nsLayoutUtils::GetStyleFrame(aFrame));
+  MOZ_ASSERT(pseudoElement,
+             "We have a valid element for the frame, if we don't we should "
+             "have bailed out at above the call to EffectSet::Get");
+  EffectCompositor::MaybeUpdateCascadeResults(pseudoElement->mElement,
+                                              pseudoElement->mPseudoType);
+
+  bool foundRunningAnimations = false;
+  for (KeyframeEffect* effect : *effects) {
+    AnimationPerformanceWarning::Type effectWarning =
+        AnimationPerformanceWarning::Type::None;
+    KeyframeEffect::MatchForCompositor matchResult =
+        effect->IsMatchForCompositor(aPropertySet, aFrame, *effects,
+                                     effectWarning);
+    if (effectWarning != AnimationPerformanceWarning::Type::None) {
+      EffectCompositor::SetPerformanceWarning(
+          aFrame, aPropertySet, AnimationPerformanceWarning(effectWarning));
+    }
+
+    if (matchResult ==
+        KeyframeEffect::MatchForCompositor::NoAndBlockThisProperty) {
+      // For a given |aFrame|, we don't want some animations of |aPropertySet|
+      // to run on the compositor and others to run on the main thread, so if
+      // any need to be synchronized with the main thread, run them all there.
+      if (aMatches) {
+        aMatches->Clear();
+      }
+      return false;
+    }
+
+    if (matchResult == KeyframeEffect::MatchForCompositor::No) {
+      continue;
+    }
+
+    if (aMatches) {
+      aMatches->AppendElement(effect->GetAnimation());
+    }
+
+    if (matchResult == KeyframeEffect::MatchForCompositor::Yes) {
+      foundRunningAnimations = true;
+    }
+  }
+
+  // If all animations we added were not currently playing animations, don't
+  // send them to the compositor.
+  if (aMatches && !foundRunningAnimations) {
+    aMatches->Clear();
+  }
+
+  MOZ_ASSERT(!foundRunningAnimations || !aMatches || !aMatches->IsEmpty(),
+             "If return value is true, matches array should be non-empty");
+
+  if (aMatches && foundRunningAnimations) {
+    aMatches->Sort(AnimationPtrComparator<RefPtr<dom::Animation>>());
+  }
+
+  return foundRunningAnimations;
+}
+
+void EffectCompositor::RequestRestyle(dom::Element* aElement,
+                                      PseudoStyleType aPseudoType,
+                                      RestyleType aRestyleType,
+                                      CascadeLevel aCascadeLevel) {
+  if (!mPresContext) {
+    // Pres context will be null after the effect compositor is disconnected.
+    return;
+  }
+
+  // Ignore animations on orphaned elements and elements in documents without
+  // a pres shell (e.g. XMLHttpRequest responseXML documents).
+  if (!nsContentUtils::GetPresShellForContent(aElement)) {
+    return;
+  }
+
+  auto& elementsToRestyle = mElementsToRestyle[aCascadeLevel];
+  PseudoElementHashEntry::KeyType key = {aElement, aPseudoType};
+
+  bool& restyleEntry = elementsToRestyle.LookupOrInsert(key, false);
+  if (aRestyleType == RestyleType::Throttled) {
+    mPresContext->PresShell()->SetNeedThrottledAnimationFlush();
+  } else {
+    // Update hashtable first in case PostRestyleForAnimation mutates it
+    // and invalidates the restyleEntry reference.
+    // (It shouldn't, but just to be sure.)
+    bool skipRestyle = std::exchange(restyleEntry, true);
+    if (!skipRestyle) {
+      PostRestyleForAnimation(aElement, aPseudoType, aCascadeLevel);
+    }
+  }
+
+  if (aRestyleType == RestyleType::Layer) {
+    mPresContext->RestyleManager()->IncrementAnimationGeneration();
+    if (auto* effectSet = EffectSet::Get(aElement, aPseudoType)) {
+      effectSet->UpdateAnimationGeneration(mPresContext);
+    }
+  }
+}
+
+void EffectCompositor::PostRestyleForAnimation(dom::Element* aElement,
+                                               PseudoStyleType aPseudoType,
+                                               CascadeLevel aCascadeLevel) {
+  if (!mPresContext) {
+    return;
+  }
+
+  // FIXME: Bug 1615083 KeyframeEffect::SetTarget() and
+  // KeyframeEffect::SetPseudoElement() may set a non-existing pseudo element,
+  // and we still have to update its style, based on the wpt. However, we don't
+  // have the generated element here, so we failed the wpt.
+  //
+  // See wpt for more info: web-animations/interfaces/KeyframeEffect/target.html
+  Element* element =
+      AnimationUtils::GetElementForRestyle(aElement, aPseudoType);
+  if (!element) {
+    return;
+  }
+
+  RestyleHint hint = aCascadeLevel == CascadeLevel::Transitions
+                         ? RestyleHint::RESTYLE_CSS_TRANSITIONS
+                         : RestyleHint::RESTYLE_CSS_ANIMATIONS;
+
+  MOZ_ASSERT(NS_IsMainThread(),
+             "Restyle request during restyling should be requested only on "
+             "the main-thread. e.g. after the parallel traversal");
+  if (ServoStyleSet::IsInServoTraversal() || mIsInPreTraverse) {
+    MOZ_ASSERT(hint == RestyleHint::RESTYLE_CSS_ANIMATIONS ||
+               hint == RestyleHint::RESTYLE_CSS_TRANSITIONS);
+
+    // We can't call Servo_NoteExplicitHints here since AtomicRefCell does not
+    // allow us mutate ElementData of the |aElement| in SequentialTask.
+    // Instead we call Servo_NoteExplicitHints for the element in PreTraverse()
+    // which will be called right before the second traversal that we do for
+    // updating CSS animations.
+    // In that case PreTraverse() will return true so that we know to do the
+    // second traversal so we don't need to post any restyle requests to the
+    // PresShell.
+    return;
+  }
+
+  MOZ_ASSERT(!mPresContext->RestyleManager()->IsInStyleRefresh());
+
+  mPresContext->PresShell()->RestyleForAnimation(element, hint);
+}
+
+void EffectCompositor::PostRestyleForThrottledAnimations() {
+  for (size_t i = 0; i < kCascadeLevelCount; i++) {
+    CascadeLevel cascadeLevel = CascadeLevel(i);
+    auto& elementSet = mElementsToRestyle[cascadeLevel];
+
+    for (auto iter = elementSet.Iter(); !iter.Done(); iter.Next()) {
+      bool& postedRestyle = iter.Data();
+      if (postedRestyle) {
+        continue;
+      }
+
+      PostRestyleForAnimation(iter.Key().mElement, iter.Key().mPseudoType,
+                              cascadeLevel);
+      postedRestyle = true;
+    }
+  }
+}
+
+void EffectCompositor::ClearRestyleRequestsFor(Element* aElement) {
+  MOZ_ASSERT(aElement);
+
+  auto& elementsToRestyle = mElementsToRestyle[CascadeLevel::Animations];
+
+  PseudoStyleType pseudoType = aElement->GetPseudoElementType();
+  if (pseudoType == PseudoStyleType::NotPseudo) {
+    PseudoElementHashEntry::KeyType notPseudoKey = {aElement,
+                                                    PseudoStyleType::NotPseudo};
+    PseudoElementHashEntry::KeyType beforePseudoKey = {aElement,
+                                                       PseudoStyleType::before};
+    PseudoElementHashEntry::KeyType afterPseudoKey = {aElement,
+                                                      PseudoStyleType::after};
+    PseudoElementHashEntry::KeyType markerPseudoKey = {aElement,
+                                                       PseudoStyleType::marker};
+
+    elementsToRestyle.Remove(notPseudoKey);
+    elementsToRestyle.Remove(beforePseudoKey);
+    elementsToRestyle.Remove(afterPseudoKey);
+    elementsToRestyle.Remove(markerPseudoKey);
+  } else if (AnimationUtils::IsSupportedPseudoForAnimations(pseudoType)) {
+    Element* parentElement = aElement->GetParentElement();
+    MOZ_ASSERT(parentElement);
+    PseudoElementHashEntry::KeyType key = {parentElement, pseudoType};
+    elementsToRestyle.Remove(key);
+  }
+}
+
+void EffectCompositor::UpdateEffectProperties(const ComputedStyle* aStyle,
+                                              Element* aElement,
+                                              PseudoStyleType aPseudoType) {
+  EffectSet* effectSet = EffectSet::Get(aElement, aPseudoType);
+  if (!effectSet) {
+    return;
+  }
+
+  // Style context (Gecko) or computed values (Stylo) change might cause CSS
+  // cascade level, e.g removing !important, so we should update the cascading
+  // result.
+  effectSet->MarkCascadeNeedsUpdate();
+
+  for (KeyframeEffect* effect : *effectSet) {
+    effect->UpdateProperties(aStyle);
+  }
+}
+
+namespace {
+class EffectCompositeOrderComparator {
+ public:
+  bool Equals(const KeyframeEffect* a, const KeyframeEffect* b) const {
+    return a == b;
+  }
+
+  bool LessThan(const KeyframeEffect* a, const KeyframeEffect* b) const {
+    MOZ_ASSERT(a->GetAnimation() && b->GetAnimation());
+    MOZ_ASSERT(
+        Equals(a, b) ||
+        a->GetAnimation()->HasLowerCompositeOrderThan(*b->GetAnimation()) !=
+            b->GetAnimation()->HasLowerCompositeOrderThan(*a->GetAnimation()));
+    return a->GetAnimation()->HasLowerCompositeOrderThan(*b->GetAnimation());
+  }
+};
+}  // namespace
+
+static void ComposeSortedEffects(
+    const nsTArray<KeyframeEffect*>& aSortedEffects,
+    const EffectSet* aEffectSet, EffectCompositor::CascadeLevel aCascadeLevel,
+    StyleAnimationValueMap* aAnimationValues) {
+  const bool isTransition =
+      aCascadeLevel == EffectCompositor::CascadeLevel::Transitions;
+  nsCSSPropertyIDSet propertiesToSkip;
+  // Transitions should be overridden by running animations of the same
+  // property per https://drafts.csswg.org/css-transitions/#application:
+  //
+  // > Implementations must add this value to the cascade if and only if that
+  // > property is not currently undergoing a CSS Animation on the same element.
+  //
+  // FIXME(emilio, bug 1606176): This should assert that
+  // aEffectSet->PropertiesForAnimationsLevel() is up-to-date, and it may not
+  // follow the spec in those cases. There are various places where we get style
+  // without flushing that would trigger the below assertion.
+  //
+  // MOZ_ASSERT_IF(aEffectSet, !aEffectSet->CascadeNeedsUpdate());
+  if (aEffectSet) {
+    propertiesToSkip =
+        isTransition ? aEffectSet->PropertiesForAnimationsLevel()
+                     : aEffectSet->PropertiesForAnimationsLevel().Inverse();
+  }
+
+  for (KeyframeEffect* effect : aSortedEffects) {
+    auto* animation = effect->GetAnimation();
+    MOZ_ASSERT(!isTransition || animation->CascadeLevel() == aCascadeLevel);
+    animation->ComposeStyle(*aAnimationValues, propertiesToSkip);
+  }
+}
+
+bool EffectCompositor::GetServoAnimationRule(
+    const dom::Element* aElement, PseudoStyleType aPseudoType,
+    CascadeLevel aCascadeLevel, StyleAnimationValueMap* aAnimationValues) {
+  MOZ_ASSERT(aAnimationValues);
+  // Gecko_GetAnimationRule should have already checked this
+  MOZ_ASSERT(nsContentUtils::GetPresShellForContent(aElement),
+             "Should not be trying to run animations on elements in documents"
+             " without a pres shell (e.g. XMLHttpRequest documents)");
+
+  EffectSet* effectSet = EffectSet::Get(aElement, aPseudoType);
+  if (!effectSet) {
+    return false;
+  }
+
+  const bool isTransition = aCascadeLevel == CascadeLevel::Transitions;
+
+  // Get a list of effects sorted by composite order.
+  nsTArray<KeyframeEffect*> sortedEffectList(effectSet->Count());
+  for (KeyframeEffect* effect : *effectSet) {
+    if (isTransition &&
+        effect->GetAnimation()->CascadeLevel() != aCascadeLevel) {
+      // We may need to use transition rules for the animations level for the
+      // case of missing keyframes in animations, but we don't ever need to look
+      // at non-transition levels to build a transition rule. When the effect
+      // set information is out of date (see above), this avoids creating bogus
+      // transition rules, see bug 1605610.
+      continue;
+    }
+    sortedEffectList.AppendElement(effect);
+  }
+
+  if (sortedEffectList.IsEmpty()) {
+    return false;
+  }
+
+  sortedEffectList.Sort(EffectCompositeOrderComparator());
+
+  ComposeSortedEffects(sortedEffectList, effectSet, aCascadeLevel,
+                       aAnimationValues);
+
+  MOZ_ASSERT(effectSet == EffectSet::Get(aElement, aPseudoType),
+             "EffectSet should not change while composing style");
+
+  return true;
+}
+
+bool EffectCompositor::ComposeServoAnimationRuleForEffect(
+    KeyframeEffect& aEffect, CascadeLevel aCascadeLevel,
+    StyleAnimationValueMap* aAnimationValues) {
+  MOZ_ASSERT(aAnimationValues);
+  MOZ_ASSERT(mPresContext && mPresContext->IsDynamic(),
+             "Should not be in print preview");
+
+  NonOwningAnimationTarget target = aEffect.GetAnimationTarget();
+  if (!target) {
+    return false;
+  }
+
+  // Don't try to compose animations for elements in documents without a pres
+  // shell (e.g. XMLHttpRequest documents).
+  if (!nsContentUtils::GetPresShellForContent(target.mElement)) {
+    return false;
+  }
+
+  // GetServoAnimationRule is called as part of the regular style resolution
+  // where the cascade results are updated in the pre-traversal as needed.
+  // This function, however, is only called when committing styles so we
+  // need to ensure the cascade results are up-to-date manually.
+  MaybeUpdateCascadeResults(target.mElement, target.mPseudoType);
+
+  EffectSet* effectSet = EffectSet::Get(target.mElement, target.mPseudoType);
+
+  // Get a list of effects sorted by composite order up to and including
+  // |aEffect|, even if it is not in the EffectSet.
+  auto comparator = EffectCompositeOrderComparator();
+  nsTArray<KeyframeEffect*> sortedEffectList(effectSet ? effectSet->Count() + 1
+                                                       : 1);
+  if (effectSet) {
+    for (KeyframeEffect* effect : *effectSet) {
+      if (comparator.LessThan(effect, &aEffect)) {
+        sortedEffectList.AppendElement(effect);
+      }
+    }
+    sortedEffectList.Sort(comparator);
+  }
+  sortedEffectList.AppendElement(&aEffect);
+
+  ComposeSortedEffects(sortedEffectList, effectSet, aCascadeLevel,
+                       aAnimationValues);
+
+  MOZ_ASSERT(effectSet == EffectSet::Get(target.mElement, target.mPseudoType),
+             "EffectSet should not change while composing style");
+
+  return true;
+}
+
+bool EffectCompositor::HasPendingStyleUpdates() const {
+  for (auto& elementSet : mElementsToRestyle) {
+    if (elementSet.Count()) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+/* static */
+bool EffectCompositor::HasAnimationsForCompositor(const nsIFrame* aFrame,
+                                                  DisplayItemType aType) {
+  return FindAnimationsForCompositor(
+      aFrame, LayerAnimationInfo::GetCSSPropertiesFor(aType), nullptr);
+}
+
+/* static */
+nsTArray<RefPtr<dom::Animation>> EffectCompositor::GetAnimationsForCompositor(
+    const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet) {
+  nsTArray<RefPtr<dom::Animation>> result;
+
+#ifdef DEBUG
+  bool foundSome =
+#endif
+      FindAnimationsForCompositor(aFrame, aPropertySet, &result);
+  MOZ_ASSERT(!foundSome || !result.IsEmpty(),
+             "If return value is true, matches array should be non-empty");
+
+  return result;
+}
+
+/* static */
+void EffectCompositor::ClearIsRunningOnCompositor(const nsIFrame* aFrame,
+                                                  DisplayItemType aType) {
+  EffectSet* effects = EffectSet::GetForFrame(aFrame, aType);
+  if (!effects) {
+    return;
+  }
+
+  const nsCSSPropertyIDSet& propertySet =
+      LayerAnimationInfo::GetCSSPropertiesFor(aType);
+  for (KeyframeEffect* effect : *effects) {
+    effect->SetIsRunningOnCompositor(propertySet, false);
+  }
+}
+
+/* static */
+void EffectCompositor::MaybeUpdateCascadeResults(Element* aElement,
+                                                 PseudoStyleType aPseudoType) {
+  EffectSet* effects = EffectSet::Get(aElement, aPseudoType);
+  if (!effects || !effects->CascadeNeedsUpdate()) {
+    return;
+  }
+
+  UpdateCascadeResults(*effects, aElement, aPseudoType);
+
+  MOZ_ASSERT(!effects->CascadeNeedsUpdate(), "Failed to update cascade state");
+}
+
+/* static */
+Maybe<NonOwningAnimationTarget>
+EffectCompositor::GetAnimationElementAndPseudoForFrame(const nsIFrame* aFrame) {
+  // Always return the same object to benefit from return-value optimization.
+  Maybe<NonOwningAnimationTarget> result;
+
+  PseudoStyleType pseudoType = aFrame->Style()->GetPseudoType();
+
+  if (pseudoType != PseudoStyleType::NotPseudo &&
+      !AnimationUtils::IsSupportedPseudoForAnimations(pseudoType)) {
+    return result;
+  }
+
+  nsIContent* content = aFrame->GetContent();
+  if (!content) {
+    return result;
+  }
+
+  if (AnimationUtils::IsSupportedPseudoForAnimations(pseudoType)) {
+    content = content->GetParent();
+    if (!content) {
+      return result;
+    }
+  }
+
+  if (!content->IsElement()) {
+    return result;
+  }
+
+  result.emplace(content->AsElement(), pseudoType);
+
+  return result;
+}
+
+/* static */
+nsCSSPropertyIDSet EffectCompositor::GetOverriddenProperties(
+    EffectSet& aEffectSet, Element* aElement, PseudoStyleType aPseudoType) {
+  MOZ_ASSERT(aElement, "Should have an element to get style data from");
+
+  nsCSSPropertyIDSet result;
+
+  Element* elementForRestyle =
+      AnimationUtils::GetElementForRestyle(aElement, aPseudoType);
+  if (!elementForRestyle) {
+    return result;
+  }
+
+  static constexpr size_t compositorAnimatableCount =
+      nsCSSPropertyIDSet::CompositorAnimatableCount();
+  AutoTArray<nsCSSPropertyID, compositorAnimatableCount> propertiesToTrack;
+  {
+    nsCSSPropertyIDSet propertiesToTrackAsSet;
+    for (KeyframeEffect* effect : aEffectSet) {
+      for (const AnimationProperty& property : effect->Properties()) {
+        if (nsCSSProps::PropHasFlags(property.mProperty,
+                                     CSSPropFlags::CanAnimateOnCompositor) &&
+            !propertiesToTrackAsSet.HasProperty(property.mProperty)) {
+          propertiesToTrackAsSet.AddProperty(property.mProperty);
+          propertiesToTrack.AppendElement(property.mProperty);
+        }
+      }
+      // Skip iterating over the rest of the effects if we've already
+      // found all the compositor-animatable properties.
+      if (propertiesToTrack.Length() == compositorAnimatableCount) {
+        break;
+      }
+    }
+  }
+
+  if (propertiesToTrack.IsEmpty()) {
+    return result;
+  }
+
+  Servo_GetProperties_Overriding_Animation(elementForRestyle,
+                                           &propertiesToTrack, &result);
+  return result;
+}
+
+/* static */
+void EffectCompositor::UpdateCascadeResults(EffectSet& aEffectSet,
+                                            Element* aElement,
+                                            PseudoStyleType aPseudoType) {
+  MOZ_ASSERT(EffectSet::Get(aElement, aPseudoType) == &aEffectSet,
+             "Effect set should correspond to the specified (pseudo-)element");
+  if (aEffectSet.IsEmpty()) {
+    aEffectSet.MarkCascadeUpdated();
+    return;
+  }
+
+  // Get a list of effects sorted by composite order.
+  nsTArray<KeyframeEffect*> sortedEffectList(aEffectSet.Count());
+  for (KeyframeEffect* effect : aEffectSet) {
+    sortedEffectList.AppendElement(effect);
+  }
+  sortedEffectList.Sort(EffectCompositeOrderComparator());
+
+  // Get properties that override the *animations* level of the cascade.
+  //
+  // We only do this for properties that we can animate on the compositor
+  // since we will apply other properties on the main thread where the usual
+  // cascade applies.
+  nsCSSPropertyIDSet overriddenProperties =
+      GetOverriddenProperties(aEffectSet, aElement, aPseudoType);
+
+  nsCSSPropertyIDSet& propertiesWithImportantRules =
+      aEffectSet.PropertiesWithImportantRules();
+  nsCSSPropertyIDSet& propertiesForAnimationsLevel =
+      aEffectSet.PropertiesForAnimationsLevel();
+
+  static constexpr nsCSSPropertyIDSet compositorAnimatables =
+      nsCSSPropertyIDSet::CompositorAnimatables();
+  // Record which compositor-animatable properties were originally set so we can
+  // compare for changes later.
+  nsCSSPropertyIDSet prevCompositorPropertiesWithImportantRules =
+      propertiesWithImportantRules.Intersect(compositorAnimatables);
+
+  nsCSSPropertyIDSet prevPropertiesForAnimationsLevel =
+      propertiesForAnimationsLevel;
+
+  propertiesWithImportantRules.Empty();
+  propertiesForAnimationsLevel.Empty();
+
+  nsCSSPropertyIDSet propertiesForTransitionsLevel;
+
+  for (const KeyframeEffect* effect : sortedEffectList) {
+    MOZ_ASSERT(effect->GetAnimation(),
+               "Effects on a target element should have an Animation");
+    CascadeLevel cascadeLevel = effect->GetAnimation()->CascadeLevel();
+
+    for (const AnimationProperty& prop : effect->Properties()) {
+      if (overriddenProperties.HasProperty(prop.mProperty)) {
+        propertiesWithImportantRules.AddProperty(prop.mProperty);
+      }
+
+      switch (cascadeLevel) {
+        case EffectCompositor::CascadeLevel::Animations:
+          propertiesForAnimationsLevel.AddProperty(prop.mProperty);
+          break;
+        case EffectCompositor::CascadeLevel::Transitions:
+          propertiesForTransitionsLevel.AddProperty(prop.mProperty);
+          break;
+      }
+    }
+  }
+
+  aEffectSet.MarkCascadeUpdated();
+
+  nsPresContext* presContext = nsContentUtils::GetContextForContent(aElement);
+  if (!presContext) {
+    return;
+  }
+
+  // If properties for compositor are newly overridden by !important rules, or
+  // released from being overridden by !important rules, we need to update
+  // layers for animations level because it's a trigger to send animations to
+  // the compositor or pull animations back from the compositor.
+  if (!prevCompositorPropertiesWithImportantRules.Equals(
+          propertiesWithImportantRules.Intersect(compositorAnimatables))) {
+    presContext->EffectCompositor()->RequestRestyle(
+        aElement, aPseudoType, EffectCompositor::RestyleType::Layer,
+        EffectCompositor::CascadeLevel::Animations);
+  }
+
+  // If we have transition properties and if the same propery for animations
+  // level is newly added or removed, we need to update the transition level
+  // rule since the it will be added/removed from the rule tree.
+  nsCSSPropertyIDSet changedPropertiesForAnimationLevel =
+      prevPropertiesForAnimationsLevel.Xor(propertiesForAnimationsLevel);
+  nsCSSPropertyIDSet commonProperties = propertiesForTransitionsLevel.Intersect(
+      changedPropertiesForAnimationLevel);
+  if (!commonProperties.IsEmpty()) {
+    EffectCompositor::RestyleType restyleType =
+        changedPropertiesForAnimationLevel.Intersects(compositorAnimatables)
+            ? EffectCompositor::RestyleType::Standard
+            : EffectCompositor::RestyleType::Layer;
+    presContext->EffectCompositor()->RequestRestyle(
+        aElement, aPseudoType, restyleType,
+        EffectCompositor::CascadeLevel::Transitions);
+  }
+}
+
+/* static */
+void EffectCompositor::SetPerformanceWarning(
+    const nsIFrame* aFrame, const nsCSSPropertyIDSet& aPropertySet,
+    const AnimationPerformanceWarning& aWarning) {
+  EffectSet* effects = EffectSet::GetForFrame(aFrame, aPropertySet);
+  if (!effects) {
+    return;
+  }
+
+  for (KeyframeEffect* effect : *effects) {
+    effect->SetPerformanceWarning(aPropertySet, aWarning);
+  }
+}
+
+bool EffectCompositor::PreTraverse(ServoTraversalFlags aFlags) {
+  return PreTraverseInSubtree(aFlags, nullptr);
+}
+
+bool EffectCompositor::PreTraverseInSubtree(ServoTraversalFlags aFlags,
+                                            Element* aRoot) {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!aRoot || nsContentUtils::GetPresShellForContent(aRoot),
+             "Traversal root, if provided, should be bound to a display "
+             "document");
+
+  // Convert the root element to the parent element if the root element is
+  // pseudo since we check each element in mElementsToRestyle is in the subtree
+  // of the root element later in this function, but for pseudo elements the
+  // element in mElementsToRestyle is the parent of the pseudo.
+  if (aRoot && (aRoot->IsGeneratedContentContainerForBefore() ||
+                aRoot->IsGeneratedContentContainerForAfter() ||
+                aRoot->IsGeneratedContentContainerForMarker())) {
+    aRoot = aRoot->GetParentElement();
+  }
+
+  AutoRestore<bool> guard(mIsInPreTraverse);
+  mIsInPreTraverse = true;
+
+  // We need to force flush all throttled animations if we also have
+  // non-animation restyles (since we'll want the up-to-date animation style
+  // when we go to process them so we can trigger transitions correctly), and
+  // if we are currently flushing all throttled animation restyles.
+  bool flushThrottledRestyles =
+      (aRoot && aRoot->HasDirtyDescendantsForServo()) ||
+      (aFlags & ServoTraversalFlags::FlushThrottledAnimations);
+
+  using ElementsToRestyleIterType =
+      nsTHashMap<PseudoElementHashEntry, bool>::ConstIterator;
+  auto getNeededRestyleTarget =
+      [&](const ElementsToRestyleIterType& aIter) -> NonOwningAnimationTarget {
+    NonOwningAnimationTarget returnTarget;
+
+    // If aIter.Data() is false, the element only requested a throttled
+    // (skippable) restyle, so we can skip it if flushThrottledRestyles is not
+    // true.
+    if (!flushThrottledRestyles && !aIter.Data()) {
+      return returnTarget;
+    }
+
+    const NonOwningAnimationTarget& target = aIter.Key();
+
+    // Skip elements in documents without a pres shell. Normally we filter out
+    // such elements in RequestRestyle but it can happen that, after adding
+    // them to mElementsToRestyle, they are transferred to a different document.
+    //
+    // We will drop them from mElementsToRestyle at the end of the next full
+    // document restyle (at the end of this function) but for consistency with
+    // how we treat such elements in RequestRestyle, we just ignore them here.
+    if (!nsContentUtils::GetPresShellForContent(target.mElement)) {
+      return returnTarget;
+    }
+
+    // Ignore restyles that aren't in the flattened tree subtree rooted at
+    // aRoot.
+    if (aRoot && !nsContentUtils::ContentIsFlattenedTreeDescendantOfForStyle(
+                     target.mElement, aRoot)) {
+      return returnTarget;
+    }
+
+    returnTarget = target;
+    return returnTarget;
+  };
+
+  bool foundElementsNeedingRestyle = false;
+
+  nsTArray<NonOwningAnimationTarget> elementsWithCascadeUpdates;
+  for (size_t i = 0; i < kCascadeLevelCount; ++i) {
+    CascadeLevel cascadeLevel = CascadeLevel(i);
+    auto& elementSet = mElementsToRestyle[cascadeLevel];
+    for (auto iter = elementSet.ConstIter(); !iter.Done(); iter.Next()) {
+      const NonOwningAnimationTarget& target = getNeededRestyleTarget(iter);
+      if (!target.mElement) {
+        continue;
+      }
+
+      EffectSet* effects = EffectSet::Get(target.mElement, target.mPseudoType);
+      if (!effects || !effects->CascadeNeedsUpdate()) {
+        continue;
+      }
+
+      elementsWithCascadeUpdates.AppendElement(target);
+    }
+  }
+
+  for (const NonOwningAnimationTarget& target : elementsWithCascadeUpdates) {
+    MaybeUpdateCascadeResults(target.mElement, target.mPseudoType);
+  }
+  elementsWithCascadeUpdates.Clear();
+
+  for (size_t i = 0; i < kCascadeLevelCount; ++i) {
+    CascadeLevel cascadeLevel = CascadeLevel(i);
+    auto& elementSet = mElementsToRestyle[cascadeLevel];
+    for (auto iter = elementSet.Iter(); !iter.Done(); iter.Next()) {
+      const NonOwningAnimationTarget& target = getNeededRestyleTarget(iter);
+      if (!target.mElement) {
+        continue;
+      }
+
+      if (target.mElement->GetComposedDoc() != mPresContext->Document()) {
+        iter.Remove();
+        continue;
+      }
+
+      // We need to post restyle hints even if the target is not in EffectSet to
+      // ensure the final restyling for removed animations.
+      // We can't call PostRestyleEvent directly here since we are still in the
+      // middle of the servo traversal.
+      mPresContext->RestyleManager()->PostRestyleEventForAnimations(
+          target.mElement, target.mPseudoType,
+          cascadeLevel == CascadeLevel::Transitions
+              ? RestyleHint::RESTYLE_CSS_TRANSITIONS
+              : RestyleHint::RESTYLE_CSS_ANIMATIONS);
+
+      foundElementsNeedingRestyle = true;
+
+      auto* effects = EffectSet::Get(target.mElement, target.mPseudoType);
+      if (!effects) {
+        // Drop EffectSets that have been destroyed.
+        iter.Remove();
+        continue;
+      }
+
+      for (KeyframeEffect* effect : *effects) {
+        effect->GetAnimation()->WillComposeStyle();
+      }
+
+      // Remove the element from the list of elements to restyle since we are
+      // about to restyle it.
+      iter.Remove();
+    }
+
+    // If this is a full document restyle, then unconditionally clear
+    // elementSet in case there are any elements that didn't match above
+    // because they were moved to a document without a pres shell after
+    // posting an animation restyle.
+    if (!aRoot && flushThrottledRestyles) {
+      elementSet.Clear();
+    }
+  }
+
+  return foundElementsNeedingRestyle;
+}
+
+void EffectCompositor::NoteElementForReducing(
+    const NonOwningAnimationTarget& aTarget) {
+  if (!StaticPrefs::dom_animations_api_autoremove_enabled()) {
+    return;
+  }
+
+  Unused << mElementsToReduce.put(
+      OwningAnimationTarget{aTarget.mElement, aTarget.mPseudoType});
+}
+
+static void ReduceEffectSet(EffectSet& aEffectSet) {
+  // Get a list of effects sorted by composite order.
+  nsTArray<KeyframeEffect*> sortedEffectList(aEffectSet.Count());
+  for (KeyframeEffect* effect : aEffectSet) {
+    sortedEffectList.AppendElement(effect);
+  }
+  sortedEffectList.Sort(EffectCompositeOrderComparator());
+
+  nsCSSPropertyIDSet setProperties;
+
+  // Iterate in reverse
+  for (auto iter = sortedEffectList.rbegin(); iter != sortedEffectList.rend();
+       ++iter) {
+    MOZ_ASSERT(*iter && (*iter)->GetAnimation(),
+               "Effect in an EffectSet should have an animation");
+    KeyframeEffect& effect = **iter;
+    Animation& animation = *effect.GetAnimation();
+    if (animation.IsRemovable() &&
+        effect.GetPropertySet().IsSubsetOf(setProperties)) {
+      animation.Remove();
+    } else if (animation.IsReplaceable()) {
+      setProperties |= effect.GetPropertySet();
+    }
+  }
+}
+
+void EffectCompositor::ReduceAnimations() {
+  for (auto iter = mElementsToReduce.iter(); !iter.done(); iter.next()) {
+    const OwningAnimationTarget& target = iter.get();
+    auto* effectSet = EffectSet::Get(target.mElement, target.mPseudoType);
+    if (effectSet) {
+      ReduceEffectSet(*effectSet);
+    }
+  }
+
+  mElementsToReduce.clear();
+}
+
+}  // namespace mozilla