--- a/devtools/client/performance/docs/markers.md
+++ b/devtools/client/performance/docs/markers.md
@@ -49,17 +49,16 @@ needs to figure out the computational st
   any amount of the following, separated via " | ". All future restyleHints
   are from `RestyleManager::RestyleHintToString`.
 
   * "eRestyle_Self"
   * "eRestyle_Subtree"
   * "eRestyle_LaterSiblings"
   * "eRestyle_CSSTransitions"
   * "eRestyle_CSSAnimations"
-  * "eRestyle_SVGAttrAnimations"
   * "eRestyle_StyleAttribute"
   * "eRestyle_StyleAttribute_Animations"
   * "eRestyle_Force"
   * "eRestyle_ForceDescendants"
 
 
 ## Javascript
 

--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -183,17 +183,16 @@
 
 // FOR CSP (autogenerated by xpidl)
 #include "nsIContentSecurityPolicy.h"
 #include "mozilla/dom/nsCSPContext.h"
 #include "mozilla/dom/nsCSPService.h"
 #include "mozilla/dom/nsCSPUtils.h"
 #include "nsHTMLStyleSheet.h"
 #include "nsHTMLCSSStyleSheet.h"
-#include "SVGAttrAnimationRuleProcessor.h"
 #include "mozilla/dom/DOMImplementation.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/Comment.h"
 #include "nsTextNode.h"
 #include "mozilla/dom/Link.h"
 #include "mozilla/dom/HTMLElementBinding.h"
 #include "nsXULAppAPI.h"
 #include "mozilla/dom/Touch.h"
@@ -2296,21 +2295,16 @@ nsDocument::ResetStylesheetsToURI(nsIURI
   } else {
     mAttrStyleSheet = new nsHTMLStyleSheet(this);
   }
 
   if (!mStyleAttrStyleSheet) {
     mStyleAttrStyleSheet = new nsHTMLCSSStyleSheet();
   }
 
-  if (!mSVGAttrAnimationRuleProcessor) {
-    mSVGAttrAnimationRuleProcessor =
-      new mozilla::SVGAttrAnimationRuleProcessor();
-  }
-
   // Now set up our style sets
   nsCOMPtr<nsIPresShell> shell = GetShell();
   if (shell) {
     FillStyleSet(shell->StyleSet());
   }
 }
 
 static void
@@ -12360,22 +12354,16 @@ nsDocument::DocAddSizeOfExcludingThis(ns
     CSSLoader()->SizeOfIncludingThis(aWindowSizes->mMallocSizeOf);
 
   aWindowSizes->mDOMOtherSize +=
     mAttrStyleSheet ?
     mAttrStyleSheet->DOMSizeOfIncludingThis(aWindowSizes->mMallocSizeOf) :
     0;
 
   aWindowSizes->mDOMOtherSize +=
-    mSVGAttrAnimationRuleProcessor ?
-    mSVGAttrAnimationRuleProcessor->DOMSizeOfIncludingThis(
-                                      aWindowSizes->mMallocSizeOf) :
-    0;
-
-  aWindowSizes->mDOMOtherSize +=
     mStyledLinks.ShallowSizeOfExcludingThis(aWindowSizes->mMallocSizeOf);
 
   aWindowSizes->mDOMOtherSize +=
     mIdentifierMap.SizeOfExcludingThis(aWindowSizes->mMallocSizeOf);
 
   // Measurement of the following members may be added later if DMD finds it
   // is worthwhile:
   // - many!

--- a/dom/base/nsIDocument.h
+++ b/dom/base/nsIDocument.h
@@ -104,17 +104,16 @@ struct nsCSSSelectorList;
 
 namespace mozilla {
 class AbstractThread;
 class CSSStyleSheet;
 class ErrorResult;
 class EventStates;
 class PendingAnimationTracker;
 class StyleSetHandle;
-class SVGAttrAnimationRuleProcessor;
 template<typename> class OwningNonNull;
 
 namespace css {
 class Loader;
 class ImageLoader;
 class Rule;
 } // namespace css
 
@@ -1277,26 +1276,16 @@ public:
   /**
    * Get this document's inline style sheet.  May return null if there
    * isn't one
    */
   nsHTMLCSSStyleSheet* GetInlineStyleSheet() const {
     return mStyleAttrStyleSheet;
   }
 
-  /**
-   * Get this document's SVG Animation rule processor.  May return null
-   * if there isn't one.
-   */
-  mozilla::SVGAttrAnimationRuleProcessor*
-  GetSVGAttrAnimationRuleProcessor() const
-  {
-    return mSVGAttrAnimationRuleProcessor;
-  }
-
   virtual void SetScriptGlobalObject(nsIScriptGlobalObject* aGlobalObject) = 0;
 
   /**
    * Get/set the object from which the context for the event/script handling can
    * be got. Normally GetScriptHandlingObject() returns the same object as
    * GetScriptGlobalObject(), but if the document is loaded as data,
    * non-null may be returned, even if GetScriptGlobalObject() returns null.
    * aHasHadScriptHandlingObject is set true if document has had the object
@@ -3017,17 +3006,16 @@ protected:
 
   // This is a weak reference, but we hold a strong reference to mNodeInfo,
   // which in turn holds a strong reference to this mNodeInfoManager.
   nsNodeInfoManager* mNodeInfoManager;
   RefPtr<mozilla::css::Loader> mCSSLoader;
   RefPtr<mozilla::css::ImageLoader> mStyleImageLoader;
   RefPtr<nsHTMLStyleSheet> mAttrStyleSheet;
   RefPtr<nsHTMLCSSStyleSheet> mStyleAttrStyleSheet;
-  RefPtr<mozilla::SVGAttrAnimationRuleProcessor> mSVGAttrAnimationRuleProcessor;
 
   // Tracking for images in the document.
   RefPtr<mozilla::dom::ImageTracker> mImageTracker;
 
   // The set of all object, embed, applet, video/audio elements or
   // nsIObjectLoadingContent or nsIDocumentActivity for which this is the
   // owner document. (They might not be in the document.)
   // These are non-owning pointers, the elements are responsible for removing

--- a/layout/base/nsChangeHint.h
+++ b/layout/base/nsChangeHint.h
@@ -538,17 +538,16 @@ enum nsRestyleHint {
   // changes.  (Implies eRestyle_Force.)  Note that this is weaker than
   // eRestyle_Subtree, which makes us rerun selector matching on all
   // descendants rather than just continuing the restyling process.
   eRestyle_ForceDescendants = 1 << 10,
 
   // Useful unions:
   eRestyle_AllHintsWithAnimations = eRestyle_CSSTransitions |
                                     eRestyle_CSSAnimations |
-                                    eRestyle_SVGAttrAnimations |
                                     eRestyle_StyleAttribute_Animations,
 };
 
 // The functions below need an integral type to cast to to avoid
 // infinite recursion.
 typedef decltype(nsRestyleHint(0) + nsRestyleHint(0)) nsRestyleHint_size_t;
 
 inline constexpr nsRestyleHint operator|(nsRestyleHint aLeft,

deleted file mode 100644
--- a/layout/style/SVGAttrAnimationRuleProcessor.cpp
+++ /dev/null
@@ -1,122 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * 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/.
- */
-
-/*
- * style rule processor for rules from SMIL Animation of SVG mapped
- * attributes (attributes whose values are mapped into style)
- */
-
-#include "SVGAttrAnimationRuleProcessor.h"
-#include "nsRuleProcessorData.h"
-#include "nsSVGElement.h"
-
-using namespace mozilla;
-using namespace mozilla::dom;
-
-SVGAttrAnimationRuleProcessor::SVGAttrAnimationRuleProcessor()
-{
-}
-
-SVGAttrAnimationRuleProcessor::~SVGAttrAnimationRuleProcessor()
-{
-}
-
-NS_IMPL_ISUPPORTS(SVGAttrAnimationRuleProcessor, nsIStyleRuleProcessor)
-
-/* virtual */ void
-SVGAttrAnimationRuleProcessor::RulesMatching(ElementRuleProcessorData* aData)
-{
-  ElementRulesMatching(aData->mElement, aData->mRuleWalker);
-}
-
-void
-SVGAttrAnimationRuleProcessor::ElementRulesMatching(Element* aElement,
-                                                    nsRuleWalker* aRuleWalker)
-{
-  if (aElement->IsSVGElement()) {
-    static_cast<nsSVGElement*>(aElement)->
-      WalkAnimatedContentStyleRules(aRuleWalker);
-  }
-}
-
-/* virtual */ nsRestyleHint
-SVGAttrAnimationRuleProcessor::HasStateDependentStyle(StateRuleProcessorData* aData)
-{
-  return nsRestyleHint(0);
-}
-
-/* virtual */ nsRestyleHint
-SVGAttrAnimationRuleProcessor::HasStateDependentStyle(PseudoElementStateRuleProcessorData* aData)
-{
-  return nsRestyleHint(0);
-}
-
-/* virtual */ bool
-SVGAttrAnimationRuleProcessor::HasDocumentStateDependentStyle(StateRuleProcessorData* aData)
-{
-  return false;
-}
-
-/* virtual */ nsRestyleHint
-SVGAttrAnimationRuleProcessor::HasAttributeDependentStyle(
-    AttributeRuleProcessorData* aData,
-    RestyleHintData& aRestyleHintDataResult)
-{
-  return nsRestyleHint(0);
-}
-
-/* virtual */ bool
-SVGAttrAnimationRuleProcessor::MediumFeaturesChanged(nsPresContext* aPresContext)
-{
-  return false;
-}
-
-/* virtual */ void
-SVGAttrAnimationRuleProcessor::RulesMatching(PseudoElementRuleProcessorData* aData)
-{
-  // If SMIL Animation of SVG attributes can ever target
-  // pseudo-elements, we need to adjust either
-  // nsStyleSet::RuleNodeWithReplacement or the test in
-  // ElementRestyler::RestyleSelf (added in bug 977991 patch 4) to
-  // handle such styles.
-}
-
-/* virtual */ void
-SVGAttrAnimationRuleProcessor::RulesMatching(AnonBoxRuleProcessorData* aData)
-{
-  // If SMIL Animation of SVG attributes can ever target anonymous boxes,
-  // see comment in RulesMatching(PseudoElementRuleProcessorData*).
-}
-
-#ifdef MOZ_XUL
-/* virtual */ void
-SVGAttrAnimationRuleProcessor::RulesMatching(XULTreeRuleProcessorData* aData)
-{
-  // If SMIL Animation of SVG attributes can ever target XUL tree pseudos,
-  // see comment in RulesMatching(PseudoElementRuleProcessorData*).
-}
-#endif
-
-/* virtual */ size_t
-SVGAttrAnimationRuleProcessor::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
-{
-  return 0; // SVGAttrAnimationRuleProcessors are charged to the DOM, not layout
-}
-
-/* virtual */ size_t
-SVGAttrAnimationRuleProcessor::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
-{
-  return 0; // SVGAttrAnimationRuleProcessors are charged to the DOM, not layout
-}
-
-size_t
-SVGAttrAnimationRuleProcessor::DOMSizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
-{
-  size_t n = aMallocSizeOf(this);
-
-  return n;
-}

deleted file mode 100644
--- a/layout/style/SVGAttrAnimationRuleProcessor.h
+++ /dev/null
@@ -1,68 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * 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/. */
-
-/*
- * style rule processor for rules from SMIL Animation of SVG mapped
- * attributes (attributes whose values are mapped into style)
- */
-
-#ifndef mozilla_SVGAttrAnimationRuleProcessor_h_
-#define mozilla_SVGAttrAnimationRuleProcessor_h_
-
-#include "nsIStyleRuleProcessor.h"
-
-class nsRuleWalker;
-
-namespace mozilla {
-
-namespace dom {
-class Element;
-} // namespace dom
-
-class SVGAttrAnimationRuleProcessor final : public nsIStyleRuleProcessor
-{
-public:
-  SVGAttrAnimationRuleProcessor();
-
-private:
-  ~SVGAttrAnimationRuleProcessor();
-
-public:
-  NS_DECL_ISUPPORTS
-
-  // nsIStyleRuleProcessor API
-  virtual void RulesMatching(ElementRuleProcessorData* aData) override;
-  virtual void RulesMatching(PseudoElementRuleProcessorData* aData) override;
-  virtual void RulesMatching(AnonBoxRuleProcessorData* aData) override;
-#ifdef MOZ_XUL
-  virtual void RulesMatching(XULTreeRuleProcessorData* aData) override;
-#endif
-  virtual nsRestyleHint HasStateDependentStyle(StateRuleProcessorData* aData) override;
-  virtual nsRestyleHint HasStateDependentStyle(PseudoElementStateRuleProcessorData* aData) override;
-  virtual bool HasDocumentStateDependentStyle(StateRuleProcessorData* aData) override;
-  virtual nsRestyleHint
-    HasAttributeDependentStyle(AttributeRuleProcessorData* aData,
-                               RestyleHintData& aRestyleHintDataResult) override;
-  virtual bool MediumFeaturesChanged(nsPresContext* aPresContext) override;
-  virtual size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf)
-    const MOZ_MUST_OVERRIDE override;
-  virtual size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf)
-    const MOZ_MUST_OVERRIDE override;
-
-  size_t DOMSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
-
-  // A shortcut for nsStyleSet to call RulesMatching with less setup.
-  void ElementRulesMatching(mozilla::dom::Element* aElement,
-                            nsRuleWalker* aRuleWalker);
-
-private:
-  SVGAttrAnimationRuleProcessor(const SVGAttrAnimationRuleProcessor& aCopy) = delete;
-  SVGAttrAnimationRuleProcessor& operator=(const SVGAttrAnimationRuleProcessor& aCopy) = delete;
-};
-
-} // namespace mozilla
-
-#endif /* !defined(mozilla_SVGAttrAnimationRuleProcessor_h_) */

--- a/layout/style/ServoMediaRule.cpp
+++ b/layout/style/ServoMediaRule.cpp
@@ -4,16 +4,17 @@
  * 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/. */
 
 /* representation of CSSMediaRule for stylo */
 
 #include "mozilla/ServoMediaRule.h"
 
 #include "mozilla/ServoBindings.h"
+#include "mozilla/ServoMediaList.h"
 
 using namespace mozilla::dom;
 
 namespace mozilla {
 
 ServoMediaRule::ServoMediaRule(RefPtr<RawServoMediaRule> aRawRule)
   : CSSMediaRule(Servo_MediaRule_GetRules(aRawRule).Consume())
   , mRawRule(Move(aRawRule))

--- a/layout/style/SheetType.h
+++ b/layout/style/SheetType.h
@@ -16,17 +16,16 @@ namespace mozilla {
 // highest (for non-!important rules).
 //
 // Be sure to update NS_RULE_NODE_LEVEL_MASK when changing the number
 // of sheet types; static assertions enforce this.
 enum class SheetType : uint8_t {
   Agent, // CSS
   User, // CSS
   PresHint,
-  SVGAttrAnimation,
   Doc, // CSS
   ScopedDoc,
   StyleAttr,
   Override, // CSS
   Animation,
   Transition,
 
   Count,

--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -223,17 +223,16 @@ UNIFIED_SOURCES += [
     'ServoNamespaceRule.cpp',
     'ServoSpecifiedValues.cpp',
     'ServoStyleRule.cpp',
     'ServoStyleSet.cpp',
     'ServoStyleSheet.cpp',
     'StyleAnimationValue.cpp',
     'StyleRule.cpp',
     'StyleSheet.cpp',
-    'SVGAttrAnimationRuleProcessor.cpp',
 ]
 
 # - nsCSSRuleProcessor.cpp needs to be built separately because it uses
 # plarena.h.
 # - nsLayoutStylesheetCache.cpp needs to be built separately because it uses
 # nsExceptionHandler.h, which includes windows.h.
 SOURCES += [
     'nsCSSRuleProcessor.cpp',

--- a/layout/style/nsStyleSet.cpp
+++ b/layout/style/nsStyleSet.cpp
@@ -31,17 +31,16 @@
 #include "nsRuleData.h"
 #include "nsRuleProcessorData.h"
 #include "nsAnimationManager.h"
 #include "nsStyleSheetService.h"
 #include "mozilla/dom/Element.h"
 #include "GeckoProfiler.h"
 #include "nsHTMLCSSStyleSheet.h"
 #include "nsHTMLStyleSheet.h"
-#include "SVGAttrAnimationRuleProcessor.h"
 #include "nsCSSRules.h"
 #include "nsPrintfCString.h"
 #include "nsIFrame.h"
 #include "mozilla/RestyleManager.h"
 #include "mozilla/RestyleManagerInlines.h"
 #include "nsQueryObject.h"
 
 #include <inttypes.h>
@@ -288,17 +287,16 @@ nsStyleSet::Init(nsPresContext *aPresCon
   mDisableTextZoomStyleRule = new nsDisableTextZoomStyleRule;
 
   mRuleTree = nsRuleNode::CreateRootNode(aPresContext);
 
   // Make an explicit GatherRuleProcessors call for the levels that
   // don't have style sheets.  The other levels will have their calls
   // triggered by DirtyRuleProcessors.
   GatherRuleProcessors(SheetType::PresHint);
-  GatherRuleProcessors(SheetType::SVGAttrAnimation);
   GatherRuleProcessors(SheetType::StyleAttr);
   GatherRuleProcessors(SheetType::Animation);
   GatherRuleProcessors(SheetType::Transition);
 }
 
 nsresult
 nsStyleSet::BeginReconstruct()
 {
@@ -473,21 +471,16 @@ nsStyleSet::GatherRuleProcessors(SheetTy
       MOZ_ASSERT(mSheets[aType].IsEmpty());
       mRuleProcessors[aType] = PresContext()->Document()->GetInlineStyleSheet();
       return NS_OK;
     case SheetType::PresHint:
       MOZ_ASSERT(mSheets[aType].IsEmpty());
       mRuleProcessors[aType] =
         PresContext()->Document()->GetAttributeStyleSheet();
       return NS_OK;
-    case SheetType::SVGAttrAnimation:
-      MOZ_ASSERT(mSheets[aType].IsEmpty());
-      mRuleProcessors[aType] =
-        PresContext()->Document()->GetSVGAttrAnimationRuleProcessor();
-      return NS_OK;
     default:
       // keep going
       break;
   }
   MOZ_ASSERT(IsCSSSheetType(aType));
   if (aType == SheetType::ScopedDoc) {
     // Create a rule processor for each scope.
     uint32_t count = mSheets[SheetType::ScopedDoc].Length();
@@ -1110,17 +1103,16 @@ nsStyleSet::FileRules(nsIStyleRuleProces
 
   NS_ASSERTION(mBatching == 0, "rule processors out of date");
 
   // Cascading order:
   // [least important]
   //  - UA normal rules                    = Agent        normal
   //  - User normal rules                  = User         normal
   //  - Presentation hints                 = PresHint     normal
-  //  - SVG Animation (highest pres hint)  = SVGAttrAnimation normal
   //  - Author normal rules                = Document     normal
   //  - Override normal rules              = Override     normal
   //  - animation rules                    = Animation    normal
   //  - Author !important rules            = Document     !important
   //  - Override !important rules          = Override     !important
   //  - User !important rules              = User         !important
   //  - UA !important rules                = Agent        !important
   //  - transition rules                   = Transition   normal
@@ -1142,21 +1134,17 @@ nsStyleSet::FileRules(nsIStyleRuleProces
   if (!skipUserStyles && mRuleProcessors[SheetType::User]) // NOTE: different
     (*aCollectorFunc)(mRuleProcessors[SheetType::User], aData);
   nsRuleNode* lastUserRN = aRuleWalker->CurrentNode();
   bool haveImportantUserRules = !aRuleWalker->GetCheckForImportantRules();
 
   aRuleWalker->SetLevel(SheetType::PresHint, false, false);
   if (mRuleProcessors[SheetType::PresHint])
     (*aCollectorFunc)(mRuleProcessors[SheetType::PresHint], aData);
-
-  aRuleWalker->SetLevel(SheetType::SVGAttrAnimation, false, false);
-  if (mRuleProcessors[SheetType::SVGAttrAnimation])
-    (*aCollectorFunc)(mRuleProcessors[SheetType::SVGAttrAnimation], aData);
-  nsRuleNode* lastSVGAttrAnimationRN = aRuleWalker->CurrentNode();
+  nsRuleNode* lastPresHintRN = aRuleWalker->CurrentNode();
 
   aRuleWalker->SetLevel(SheetType::Doc, false, true);
   bool cutOffInheritance = false;
   if (mBindingManager && aElement) {
     // We can supply additional document-level sheets that should be walked.
     mBindingManager->WalkRules(aCollectorFunc,
                                static_cast<ElementDependentRuleProcessorData*>(aData),
                                &cutOffInheritance);
@@ -1220,21 +1208,21 @@ nsStyleSet::FileRules(nsIStyleRuleProces
 #ifdef DEBUG
   else {
     AssertNoImportantRules(lastScopedRN, lastDocRN);
   }
 #endif
 
   if (haveImportantDocRules) {
     aRuleWalker->SetLevel(SheetType::Doc, true, false);
-    AddImportantRules(lastDocRN, lastSVGAttrAnimationRN, aRuleWalker);  // doc
+    AddImportantRules(lastDocRN, lastPresHintRN, aRuleWalker);  // doc
   }
 #ifdef DEBUG
   else {
-    AssertNoImportantRules(lastDocRN, lastSVGAttrAnimationRN);
+    AssertNoImportantRules(lastDocRN, lastPresHintRN);
   }
 #endif
 
   if (haveImportantStyleAttrRules) {
     aRuleWalker->SetLevel(SheetType::StyleAttr, true, false);
     AddImportantRules(lastStyleAttrRN, lastScopedRN, aRuleWalker);  // style attr
   }
 #ifdef DEBUG
@@ -1249,17 +1237,17 @@ nsStyleSet::FileRules(nsIStyleRuleProces
   }
 #ifdef DEBUG
   else {
     AssertNoImportantRules(lastOvrRN, lastStyleAttrRN);
   }
 #endif
 
 #ifdef DEBUG
-  AssertNoCSSRules(lastSVGAttrAnimationRN, lastUserRN);
+  AssertNoCSSRules(lastPresHintRN, lastUserRN);
 #endif
 
   if (haveImportantUserRules) {
     aRuleWalker->SetLevel(SheetType::User, true, false);
     AddImportantRules(lastUserRN, lastAgentRN, aRuleWalker); //user
   }
 #ifdef DEBUG
   else {
@@ -1306,19 +1294,16 @@ nsStyleSet::WalkRuleProcessors(nsIStyleR
 
   bool skipUserStyles = aData->mElement->IsInNativeAnonymousSubtree();
   if (!skipUserStyles && mRuleProcessors[SheetType::User]) // NOTE: different
     (*aFunc)(mRuleProcessors[SheetType::User], aData);
 
   if (mRuleProcessors[SheetType::PresHint])
     (*aFunc)(mRuleProcessors[SheetType::PresHint], aData);
 
-  if (mRuleProcessors[SheetType::SVGAttrAnimation])
-    (*aFunc)(mRuleProcessors[SheetType::SVGAttrAnimation], aData);
-
   bool cutOffInheritance = false;
   if (mBindingManager) {
     // We can supply additional document-level sheets that should be walked.
     if (aWalkAllXBLStylesheets) {
       mBindingManager->WalkAllRules(aFunc, aData);
     } else {
       mBindingManager->WalkRules(aFunc, aData, &cutOffInheritance);
     }
@@ -1492,17 +1477,16 @@ struct CascadeLevel {
   bool mCheckForImportantRules;
   nsRestyleHint mLevelReplacementHint;
 };
 
 static const CascadeLevel gCascadeLevels[] = {
   { SheetType::Agent,            false, false, nsRestyleHint(0) },
   { SheetType::User,             false, false, nsRestyleHint(0) },
   { SheetType::PresHint,         false, false, nsRestyleHint(0) },
-  { SheetType::SVGAttrAnimation, false, false, eRestyle_SVGAttrAnimations },
   { SheetType::Doc,              false, false, nsRestyleHint(0) },
   { SheetType::ScopedDoc,        false, false, nsRestyleHint(0) },
   { SheetType::StyleAttr,        false, true,  eRestyle_StyleAttribute |
                                                eRestyle_StyleAttribute_Animations },
   { SheetType::Override,         false, false, nsRestyleHint(0) },
   { SheetType::Animation,        false, false, eRestyle_CSSAnimations },
   { SheetType::ScopedDoc,        true,  false, nsRestyleHint(0) },
   { SheetType::Doc,              true,  false, nsRestyleHint(0) },
@@ -1530,17 +1514,16 @@ nsStyleSet::RuleNodeWithReplacement(Elem
              "should have aPseudoElement only for certain pseudo elements");
 
   // Remove the Force bits, which we don't need and which could confuse
   // the remainingReplacements code below.
   aReplacements &= ~(eRestyle_Force | eRestyle_ForceDescendants);
 
   MOZ_ASSERT(!(aReplacements & ~(eRestyle_CSSTransitions |
                                  eRestyle_CSSAnimations |
-                                 eRestyle_SVGAttrAnimations |
                                  eRestyle_StyleAttribute |
                                  eRestyle_StyleAttribute_Animations)),
              "unexpected replacement bits");
 
   // This array can be hot and often grows to ~20 elements, so inline storage
   // is best.
   AutoTArray<RuleNodeInfo, 30> rules;
 
@@ -1650,26 +1633,16 @@ nsStyleSet::RuleNodeWithReplacement(Elem
                                nullptr);
             if (rule) {
               ruleWalker.ForwardOnPossiblyCSSRule(rule);
               ruleWalker.CurrentNode()->SetIsAnimationRule();
             }
           }
           break;
         }
-        case SheetType::SVGAttrAnimation: {
-          SVGAttrAnimationRuleProcessor* ruleProcessor =
-            static_cast<SVGAttrAnimationRuleProcessor*>(
-              mRuleProcessors[SheetType::SVGAttrAnimation].get());
-          if (ruleProcessor &&
-              aPseudoType == CSSPseudoElementType::NotPseudo) {
-            ruleProcessor->ElementRulesMatching(aElement, &ruleWalker);
-          }
-          break;
-        }
         case SheetType::StyleAttr: {
           if (!level->mIsImportant) {
             // First time through, we handle the non-!important rule.
             nsHTMLCSSStyleSheet* ruleProcessor =
               static_cast<nsHTMLCSSStyleSheet*>(
                 mRuleProcessors[SheetType::StyleAttr].get());
             if (ruleProcessor) {
               lastScopedRN = ruleWalker.CurrentNode();