diff --git a/dom/animation/Animation.cpp b/dom/animation/Animation.cpp
index bae2df4f2c23..3346ad1274d5 100644
--- a/dom/animation/Animation.cpp
+++ b/dom/animation/Animation.cpp
@@ -1525,8 +1525,8 @@ Animation::ComposeStyle<RefPtr<AnimValuesStyleRule>&>(
 
 template
 void
-Animation::ComposeStyle<const RawServoAnimationValueMap&>(
-  const RawServoAnimationValueMap& aAnimationValues,
+Animation::ComposeStyle<RawServoAnimationValueMap&>(
+  RawServoAnimationValueMap& aAnimationValues,
   const nsCSSPropertyIDSet& aPropertiesToSkip);
 
 } // namespace dom
diff --git a/dom/animation/EffectCompositor.cpp b/dom/animation/EffectCompositor.cpp
index fa33912f4692..d1448939c8df 100644
--- a/dom/animation/EffectCompositor.cpp
+++ b/dom/animation/EffectCompositor.cpp
@@ -476,7 +476,7 @@ EffectCompositor::GetServoAnimationRule(
   const dom::Element* aElement,
   CSSPseudoElementType aPseudoType,
   CascadeLevel aCascadeLevel,
-  RawServoAnimationValueMapBorrowed aAnimationValues)
+  RawServoAnimationValueMapBorrowedMut aAnimationValues)
 {
   MOZ_ASSERT(aAnimationValues);
   MOZ_ASSERT(mPresContext && mPresContext->IsDynamic(),
diff --git a/dom/animation/EffectCompositor.h b/dom/animation/EffectCompositor.h
index 4c2dc9385d98..12df1f2cc601 100644
--- a/dom/animation/EffectCompositor.h
+++ b/dom/animation/EffectCompositor.h
@@ -25,7 +25,7 @@ class nsIStyleRule;
 class nsPresContext;
 class nsStyleContext;
 struct RawServoAnimationValueMap;
-typedef RawServoAnimationValueMap const* RawServoAnimationValueMapBorrowed;
+typedef RawServoAnimationValueMap* RawServoAnimationValueMapBorrowedMut;
 
 namespace mozilla {
 
@@ -163,7 +163,7 @@ public:
     const dom::Element* aElement,
     CSSPseudoElementType aPseudoType,
     CascadeLevel aCascadeLevel,
-    RawServoAnimationValueMapBorrowed aAnimationValues);
+    RawServoAnimationValueMapBorrowedMut aAnimationValues);
 
   bool HasPendingStyleUpdates() const;
   bool HasThrottledStyleUpdates() const;
diff --git a/dom/animation/KeyframeEffectReadOnly.cpp b/dom/animation/KeyframeEffectReadOnly.cpp
index 8895259c57f9..74ebd40565b7 100644
--- a/dom/animation/KeyframeEffectReadOnly.cpp
+++ b/dom/animation/KeyframeEffectReadOnly.cpp
@@ -661,7 +661,7 @@ KeyframeEffectReadOnly::ComposeStyleRule(
 // better to remove the duplicated code.
 void
 KeyframeEffectReadOnly::ComposeStyleRule(
-  const RawServoAnimationValueMap& aAnimationValues,
+  RawServoAnimationValueMap& aAnimationValues,
   const AnimationProperty& aProperty,
   const AnimationPropertySegment& aSegment,
   const ComputedTiming& aComputedTiming)
@@ -1881,8 +1881,8 @@ KeyframeEffectReadOnly::ComposeStyle<RefPtr<AnimValuesStyleRule>&>(
 
 template
 void
-KeyframeEffectReadOnly::ComposeStyle<const RawServoAnimationValueMap&>(
-  const RawServoAnimationValueMap& aAnimationValues,
+KeyframeEffectReadOnly::ComposeStyle<RawServoAnimationValueMap&>(
+  RawServoAnimationValueMap& aAnimationValues,
   const nsCSSPropertyIDSet& aPropertiesToSkip);
 
 } // namespace dom
diff --git a/dom/animation/KeyframeEffectReadOnly.h b/dom/animation/KeyframeEffectReadOnly.h
index 26e10065c876..b225762c3f26 100644
--- a/dom/animation/KeyframeEffectReadOnly.h
+++ b/dom/animation/KeyframeEffectReadOnly.h
@@ -431,7 +431,7 @@ private:
                         const AnimationPropertySegment& aSegment,
                         const ComputedTiming& aComputedTiming);
 
-  void ComposeStyleRule(const RawServoAnimationValueMap& aAnimationValues,
+  void ComposeStyleRule(RawServoAnimationValueMap& aAnimationValues,
                         const AnimationProperty& aProperty,
                         const AnimationPropertySegment& aSegment,
                         const ComputedTiming& aComputedTiming);
diff --git a/layout/style/ServoArcTypeList.h b/layout/style/ServoArcTypeList.h
index 2bf02e1bb190..8e54d0184d7f 100644
--- a/layout/style/ServoArcTypeList.h
+++ b/layout/style/ServoArcTypeList.h
@@ -13,7 +13,6 @@ SERVO_ARC_TYPE(DeclarationBlock, RawServoDeclarationBlock)
 SERVO_ARC_TYPE(StyleRule, RawServoStyleRule)
 SERVO_ARC_TYPE(ImportRule, RawServoImportRule)
 SERVO_ARC_TYPE(AnimationValue, RawServoAnimationValue)
-SERVO_ARC_TYPE(AnimationValueMap, RawServoAnimationValueMap)
 SERVO_ARC_TYPE(MediaList, RawServoMediaList)
 SERVO_ARC_TYPE(MediaRule, RawServoMediaRule)
 SERVO_ARC_TYPE(NamespaceRule, RawServoNamespaceRule)
diff --git a/layout/style/ServoBindingList.h b/layout/style/ServoBindingList.h
index 39acb36c0fda..3799ffcba255 100644
--- a/layout/style/ServoBindingList.h
+++ b/layout/style/ServoBindingList.h
@@ -148,7 +148,7 @@ SERVO_BINDING_FUNC(Servo_GetComputedKeyframeValues, void,
                    RawServoStyleSetBorrowed set,
                    RawGeckoComputedKeyframeValuesListBorrowedMut result)
 SERVO_BINDING_FUNC(Servo_AnimationValueMap_Push, void,
-                   RawServoAnimationValueMapBorrowed,
+                   RawServoAnimationValueMapBorrowedMut,
                    nsCSSPropertyID property,
                    RawServoAnimationValueBorrowed value)
 SERVO_BINDING_FUNC(Servo_ComputedValues_ExtractAnimationValue,
@@ -244,7 +244,7 @@ SERVO_BINDING_FUNC(Servo_DeclarationBlock_HasCSSWideKeyword, bool,
 // |base_values| is nsRefPtrHashtable<nsUint32HashKey, RawServoAnimationValue>.
 // We use void* to avoid exposing nsRefPtrHashtable in FFI.
 SERVO_BINDING_FUNC(Servo_AnimationCompose, void,
-                   RawServoAnimationValueMapBorrowed animation_values,
+                   RawServoAnimationValueMapBorrowedMut animation_values,
                    void* base_values,
                    nsCSSPropertyID property,
                    RawGeckoAnimationPropertySegmentBorrowed animation_segment,
diff --git a/layout/style/ServoBindingTypes.h b/layout/style/ServoBindingTypes.h
index 16ed3c60e289..67a6d425c186 100644
--- a/layout/style/ServoBindingTypes.h
+++ b/layout/style/ServoBindingTypes.h
@@ -14,6 +14,7 @@
 #include "nsTArray.h"
 
 struct RawServoStyleSet;
+struct RawServoAnimationValueMap;
 
 #define SERVO_ARC_TYPE(name_, type_) struct type_;
 #include "mozilla/ServoArcTypeList.h"
@@ -108,6 +109,7 @@ DECL_OWNED_REF_TYPE_FOR(RawServoStyleSet)
 DECL_NULLABLE_OWNED_REF_TYPE_FOR(StyleChildrenIterator)
 DECL_OWNED_REF_TYPE_FOR(StyleChildrenIterator)
 DECL_OWNED_REF_TYPE_FOR(ServoElementSnapshot)
+DECL_OWNED_REF_TYPE_FOR(RawServoAnimationValueMap)
 
 // We don't use BorrowedMut because the nodes may alias
 // Servo itself doesn't directly read or mutate these;
diff --git a/layout/style/ServoBindings.cpp b/layout/style/ServoBindings.cpp
index 1cd53e46c4b9..b1c891ba7bed 100644
--- a/layout/style/ServoBindings.cpp
+++ b/layout/style/ServoBindings.cpp
@@ -461,7 +461,7 @@ PseudoTagAndCorrectElementForAnimation(const Element*& aElementOrPseudo) {
 bool
 Gecko_GetAnimationRule(RawGeckoElementBorrowed aElement,
                        EffectCompositor::CascadeLevel aCascadeLevel,
-                       RawServoAnimationValueMapBorrowed aAnimationValues)
+                       RawServoAnimationValueMapBorrowedMut aAnimationValues)
 {
   MOZ_ASSERT(aElement);
 
diff --git a/layout/style/ServoBindings.h b/layout/style/ServoBindings.h
index 37e7df01acf3..e9cd0cb0d8bc 100644
--- a/layout/style/ServoBindings.h
+++ b/layout/style/ServoBindings.h
@@ -193,7 +193,7 @@ Gecko_GetExtraContentStyleDeclarations(RawGeckoElementBorrowed element);
 bool
 Gecko_GetAnimationRule(RawGeckoElementBorrowed aElementOrPseudo,
                        mozilla::EffectCompositor::CascadeLevel aCascadeLevel,
-                       RawServoAnimationValueMapBorrowed aAnimationValues);
+                       RawServoAnimationValueMapBorrowedMut aAnimationValues);
 RawServoDeclarationBlockStrongBorrowedOrNull
 Gecko_GetSMILOverrideDeclarationBlock(RawGeckoElementBorrowed element);
 bool Gecko_StyleAnimationsEquals(RawGeckoStyleAnimationListBorrowed,