--- a/dom/animation/KeyframeEffectReadOnly.cpp
+++ b/dom/animation/KeyframeEffectReadOnly.cpp
@@ -551,17 +551,16 @@ KeyframeEffectReadOnly::EnsureBaseStyle(
   if (!hasAdditiveValues) {
     return;
   }
 
   if (!aBaseStyleContext) {
     aBaseStyleContext =
       aPresContext->StyleSet()->AsServo()->GetBaseContextForElement(
           mTarget->mElement,
-          nullptr,
           aPresContext,
           nullptr,
           aPseudoType,
           aComputedStyle);
   }
   RefPtr<RawServoAnimationValue> baseValue =
     Servo_ComputedValues_ExtractAnimationValue(aBaseStyleContext,
                                                aProperty.mProperty).Consume();

--- a/layout/style/ServoStyleSet.cpp
+++ b/layout/style/ServoStyleSet.cpp
@@ -339,17 +339,17 @@ already_AddRefed<ServoStyleContext>
 ServoStyleSet::ResolveStyleFor(Element* aElement,
                                ServoStyleContext* aParentContext,
                                LazyComputeBehavior aMayCompute)
 {
   RefPtr<ServoStyleContext> computedValues;
   if (aMayCompute == LazyComputeBehavior::Allow) {
     PreTraverseSync();
     return ResolveStyleLazilyInternal(
-        aElement, CSSPseudoElementType::NotPseudo, nullptr, aParentContext);
+        aElement, CSSPseudoElementType::NotPseudo, nullptr);
   }
 
   return ResolveServoStyle(aElement);
 }
 
 /**
  * Clears any stale Servo element data that might existing in the specified
  * element's document.  Upon destruction, asserts that the element and all
@@ -618,17 +618,17 @@ ServoStyleSet::ResolveStyleLazily(Elemen
   // undisplayed element with the caller's style set's rules, but inherit from
   // values that were computed with the style set from the target element's
   // hidden-by-the-bfcache-entry pres shell.
   bool ignoreExistingStyles = aElement->OwnerDoc()->GetBFCacheEntry();
 
   AutoClearStaleData guard(aElement);
   PreTraverseSync();
   return ResolveStyleLazilyInternal(aElement, aPseudoType, aPseudoTag,
-                                    nullptr, aRuleInclusion,
+                                    aRuleInclusion,
                                     ignoreExistingStyles);
 }
 
 already_AddRefed<ServoStyleContext>
 ServoStyleSet::ResolveInheritingAnonymousBoxStyle(nsIAtom* aPseudoTag,
                                                   ServoStyleContext* aParentContext)
 {
   MOZ_ASSERT(nsCSSAnonBoxes::IsAnonBox(aPseudoTag) &&
@@ -1215,17 +1215,16 @@ ServoStyleSet::GetAnimationValues(
                            aStyleContext,
                            mRawSet.get(),
                            &aAnimationValues);
 }
 
 already_AddRefed<ServoStyleContext>
 ServoStyleSet::GetBaseContextForElement(
   Element* aElement,
-  ServoStyleContext* aParentContext,
   nsPresContext* aPresContext,
   nsIAtom* aPseudoTag,
   CSSPseudoElementType aPseudoType,
   const ServoStyleContext* aStyle)
 {
   // Servo_StyleSet_GetBaseComputedValuesForElement below won't handle ignoring
   // existing element data for bfcached documents. (See comment in
   // ResolveStyleLazily about these bfcache issues.)
@@ -1332,17 +1331,16 @@ ServoStyleSet::ClearNonInheritingStyleCo
     ptr = nullptr;
   }
 }
 
 already_AddRefed<ServoStyleContext>
 ServoStyleSet::ResolveStyleLazilyInternal(Element* aElement,
                                           CSSPseudoElementType aPseudoType,
                                           nsIAtom* aPseudoTag,
-                                          const ServoStyleContext* aParentContext,
                                           StyleRuleInclusion aRuleInclusion,
                                           bool aIgnoreExistingStyles)
 {
   mPresContext->EffectCompositor()->PreTraverse(aElement, aPseudoType);
   MOZ_ASSERT(!StylistNeedsUpdate());
 
   AutoSetInServoTraversal guard(this);
 

--- a/layout/style/ServoStyleSet.h
+++ b/layout/style/ServoStyleSet.h
@@ -384,17 +384,16 @@ public:
 
   nsCSSCounterStyleRule* CounterStyleRuleForName(nsIAtom* aName);
 
   // Get all the currently-active font feature values set.
   already_AddRefed<gfxFontFeatureValueSet> BuildFontFeatureValueSet();
 
   already_AddRefed<ServoStyleContext>
   GetBaseContextForElement(dom::Element* aElement,
-                           ServoStyleContext* aParentContext,
                            nsPresContext* aPresContext,
                            nsIAtom* aPseudoTag,
                            CSSPseudoElementType aPseudoType,
                            const ServoStyleContext* aStyle);
 
   /**
    * Resolve style for a given declaration block with/without the parent style.
    * If the parent style is not specified, the document default computed values
@@ -555,17 +554,16 @@ private:
    * This should only be called if StylistNeedsUpdate returns true.
    */
   void UpdateStylist();
 
   already_AddRefed<ServoStyleContext>
     ResolveStyleLazilyInternal(dom::Element* aElement,
                                CSSPseudoElementType aPseudoType,
                                nsIAtom* aPseudoTag,
-                               const ServoStyleContext* aParentContext,
                                StyleRuleInclusion aRules =
                                  StyleRuleInclusion::All,
                                bool aIgnoreExistingStyles = false);
 
   void RunPostTraversalTasks();
 
   void PrependSheetOfType(SheetType aType,
                           ServoStyleSheet* aSheet);

--- a/layout/style/nsComputedDOMStyle.cpp
+++ b/layout/style/nsComputedDOMStyle.cpp
@@ -709,17 +709,17 @@ nsComputedDOMStyle::DoGetStyleContextNoF
           MOZ_ASSERT(presContext, "Should have a prescontext if we have a frame");
           if (presContext && presContext->StyleSet()->IsGecko()) {
             nsStyleSet* styleSet = presContext->StyleSet()->AsGecko();
             return styleSet->ResolveStyleByRemovingAnimation(
                      aElement, result->AsGecko(),
                      eRestyle_AllHintsWithAnimations);
           } else {
             return presContext->StyleSet()->AsServo()->
-              GetBaseContextForElement(aElement, nullptr, presContext,
+              GetBaseContextForElement(aElement, presContext,
                                        aPseudo, pseudoType, result->AsServo());
           }
         }
 
         // this function returns an addrefed style context
         RefPtr<nsStyleContext> ret = result;
         return ret.forget();
       }
@@ -742,17 +742,17 @@ nsComputedDOMStyle::DoGetStyleContextNoF
                                ? StyleRuleInclusion::DefaultOnly
                                : StyleRuleInclusion::All;
     RefPtr<ServoStyleContext> result =
        servoSet->ResolveStyleLazily(aElement, pseudoType, aPseudo, rules);
     if (aAnimationFlag == eWithAnimation) {
       return result.forget();
     }
 
-    return servoSet->GetBaseContextForElement(aElement, nullptr, presContext,
+    return servoSet->GetBaseContextForElement(aElement, presContext,
                                               aPseudo, pseudoType, result);
   }
 
   RefPtr<GeckoStyleContext> parentContext;
   nsIContent* parent = aPseudo ? aElement : aElement->GetParent();
   // Don't resolve parent context for document fragments.
   if (parent && parent->IsElement()) {
     RefPtr<nsStyleContext> p =