diff --git a/layout/style/nsAnimationManager.cpp b/layout/style/nsAnimationManager.cpp
index f0ba33f15b57..e8e31fa24dcf 100644
--- a/layout/style/nsAnimationManager.cpp
+++ b/layout/style/nsAnimationManager.cpp
@@ -473,13 +473,14 @@ private:
 static Maybe<ComputedTimingFunction>
 ConvertTimingFunction(const nsTimingFunction& aTimingFunction);
 
+template<class BuilderType>
 static void
 UpdateOldAnimationPropertiesWithNew(
     CSSAnimation& aOld,
     TimingParams& aNewTiming,
     nsTArray<Keyframe>&& aNewKeyframes,
     bool aNewIsStylePaused,
-    CSSAnimationBuilder& aBuilder)
+    BuilderType& aBuilder)
 {
   bool animationChanged = false;
 
@@ -526,11 +527,12 @@ UpdateOldAnimationPropertiesWithNew(
 // Returns a new animation set up with given StyleAnimation.
 // Or returns an existing animation matching StyleAnimation's name updated
 // with the new StyleAnimation.
+template<class BuilderType>
 static already_AddRefed<CSSAnimation>
 BuildAnimation(nsPresContext* aPresContext,
                const NonOwningAnimationTarget& aTarget,
                const StyleAnimation& aSrc,
-               CSSAnimationBuilder& aBuilder,
+               BuilderType& aBuilder,
                nsAnimationManager::CSSAnimationCollection* aCollection)
 {
   MOZ_ASSERT(aPresContext);
@@ -1030,12 +1032,13 @@ CSSAnimationBuilder::GetComputedValue(nsPresContext* aPresContext,
   return result;
 }
 
+template<class BuilderType>
 static nsAnimationManager::OwningCSSAnimationPtrArray
 BuildAnimations(nsPresContext* aPresContext,
                 const NonOwningAnimationTarget& aTarget,
                 const nsStyleAutoArray<StyleAnimation>& aStyleAnimations,
                 uint32_t aStyleAnimationNameCount,
-                CSSAnimationBuilder& aBuilder,
+                BuilderType& aBuilder,
                 nsAnimationManager::CSSAnimationCollection* aCollection)
 {
   nsAnimationManager::OwningCSSAnimationPtrArray result;
@@ -1089,11 +1092,12 @@ nsAnimationManager::UpdateAnimations(nsStyleContext* aStyleContext,
   DoUpdateAnimations(target, *disp, builder);
 }
 
+template<class BuilderType>
 void
 nsAnimationManager::DoUpdateAnimations(
   const NonOwningAnimationTarget& aTarget,
   const nsStyleDisplay& aStyleDisplay,
-  CSSAnimationBuilder& aBuilder)
+  BuilderType& aBuilder)
 {
   // Everything that causes our animation data to change triggers a
   // style change, which in turn triggers a non-animation restyle.
diff --git a/layout/style/nsAnimationManager.h b/layout/style/nsAnimationManager.h
index f67e1d129562..3c2ab74b3255 100644
--- a/layout/style/nsAnimationManager.h
+++ b/layout/style/nsAnimationManager.h
@@ -15,7 +15,6 @@
 
 class nsIGlobalObject;
 class nsStyleContext;
-class CSSAnimationBuilder; // tentative, will be removed
 struct nsStyleDisplay;
 
 namespace mozilla {
@@ -357,10 +356,11 @@ protected:
   ~nsAnimationManager() override = default;
 
 private:
+  template<class BuilderType>
   void DoUpdateAnimations(
     const mozilla::NonOwningAnimationTarget& aTarget,
     const nsStyleDisplay& aStyleDisplay,
-    CSSAnimationBuilder& aBuilder);
+    BuilderType& aBuilder);
 
   mozilla::DelayedEventDispatcher<mozilla::AnimationEventInfo> mEventDispatcher;
 };