--- a/dom/animation/KeyframeEffect.cpp
+++ b/dom/animation/KeyframeEffect.cpp
@@ -668,29 +668,16 @@ KeyframeEffectReadOnly::ConstructKeyfram
   }
 
   TimingParams timingParams =
     TimingParams::FromOptionsUnion(aOptions, doc, aRv);
   if (aRv.Failed()) {
     return nullptr;
   }
 
-  return ConstructKeyframeEffect<KeyframeEffectType>(
-    aGlobal, aTarget, aFrames, timingParams, aRv);
-}
-
-template <class KeyframeEffectType>
-/* static */ already_AddRefed<KeyframeEffectType>
-KeyframeEffectReadOnly::ConstructKeyframeEffect(
-    const GlobalObject& aGlobal,
-    const Nullable<ElementOrCSSPseudoElement>& aTarget,
-    JS::Handle<JSObject*> aFrames,
-    const TimingParams& aTiming,
-    ErrorResult& aRv)
-{
   if (aTarget.IsNull()) {
     // We don't support null targets yet.
     aRv.Throw(NS_ERROR_DOM_ANIM_NO_TARGET_ERR);
     return nullptr;
   }
 
   const ElementOrCSSPseudoElement& target = aTarget.Value();
   MOZ_ASSERT(target.IsElement() || target.IsCSSPseudoElement(),
@@ -715,17 +702,17 @@ KeyframeEffectReadOnly::ConstructKeyfram
                              aFrames, animationProperties, aRv);
 
   if (aRv.Failed()) {
     return nullptr;
   }
 
   RefPtr<KeyframeEffectType> effect =
     new KeyframeEffectType(targetElement->OwnerDoc(), targetElement,
-                           pseudoType, aTiming);
+                           pseudoType, timingParams);
   effect->mProperties = Move(animationProperties);
   return effect.forget();
 }
 
 void
 KeyframeEffectReadOnly::ResetIsRunningOnCompositor()
 {
   for (AnimationProperty& property : mProperties) {
@@ -2245,21 +2232,21 @@ KeyframeEffect::Constructor(
                                                  aOptions, aRv);
 }
 
 /* static */ already_AddRefed<KeyframeEffect>
 KeyframeEffect::Constructor(
     const GlobalObject& aGlobal,
     const Nullable<ElementOrCSSPseudoElement>& aTarget,
     JS::Handle<JSObject*> aFrames,
-    const TimingParams& aTiming,
+    const UnrestrictedDoubleOrKeyframeAnimationOptions& aOptions,
     ErrorResult& aRv)
 {
   return ConstructKeyframeEffect<KeyframeEffect>(aGlobal, aTarget, aFrames,
-                                                 aTiming, aRv);
+                                                 aOptions, aRv);
 }
 
 void KeyframeEffect::NotifySpecifiedTimingUpdated()
 {
   nsIDocument* doc = nullptr;
   // Bug 1249219:
   // We don't support animation mutation observers on pseudo-elements yet.
   if (mTarget &&

--- a/dom/animation/KeyframeEffect.h
+++ b/dom/animation/KeyframeEffect.h
@@ -347,23 +347,16 @@ protected:
 
   template<class KeyframeEffectType, class OptionsType>
   static already_AddRefed<KeyframeEffectType>
   ConstructKeyframeEffect(const GlobalObject& aGlobal,
                           const Nullable<ElementOrCSSPseudoElement>& aTarget,
                           JS::Handle<JSObject*> aFrames,
                           const OptionsType& aOptions,
                           ErrorResult& aRv);
-  template<class KeyframeEffectType>
-  static already_AddRefed<KeyframeEffectType>
-  ConstructKeyframeEffect(const GlobalObject& aGlobal,
-                          const Nullable<ElementOrCSSPseudoElement>& aTarget,
-                          JS::Handle<JSObject*> aFrames,
-                          const TimingParams& aTiming,
-                          ErrorResult& aRv);
 
   void ResetIsRunningOnCompositor();
 
   // This effect is registered with its target element so long as:
   //
   // (a) It has a target element, and
   // (b) It is "relevant" (i.e. yet to finish but not idle, or finished but
   //     filling forwards)
@@ -428,23 +421,24 @@ public:
 
   static already_AddRefed<KeyframeEffect>
   Constructor(const GlobalObject& aGlobal,
               const Nullable<ElementOrCSSPseudoElement>& aTarget,
               JS::Handle<JSObject*> aFrames,
               const UnrestrictedDoubleOrKeyframeEffectOptions& aOptions,
               ErrorResult& aRv);
 
-  // More generalized version of Constructor for Animatable.animate.
+  // Variant of Constructor that accepts a KeyframeAnimationOptions object
+  // for use with for Animatable.animate.
   // Not exposed to content.
   static already_AddRefed<KeyframeEffect>
   Constructor(const GlobalObject& aGlobal,
               const Nullable<ElementOrCSSPseudoElement>& aTarget,
               JS::Handle<JSObject*> aFrames,
-              const TimingParams& aTiming,
+              const UnrestrictedDoubleOrKeyframeAnimationOptions& aOptions,
               ErrorResult& aRv);
 
   void NotifySpecifiedTimingUpdated();
 
 protected:
   ~KeyframeEffect() override;
 };
 

--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -3348,25 +3348,18 @@ Element::Animate(const Nullable<ElementO
   if (js::GetContextCompartment(aContext) !=
       js::GetObjectCompartment(ownerGlobal->GetGlobalJSObject())) {
     ac.emplace(aContext, ownerGlobal->GetGlobalJSObject());
     if (!JS_WrapObject(aContext, &frames)) {
       return nullptr;
     }
   }
 
-  TimingParams timingParams =
-    TimingParams::FromOptionsUnion(aOptions, referenceElement->OwnerDoc(),
-                                   aError);
-  if (aError.Failed()) {
-    return nullptr;
-  }
-
   RefPtr<KeyframeEffect> effect =
-    KeyframeEffect::Constructor(global, aTarget, frames, timingParams, aError);
+    KeyframeEffect::Constructor(global, aTarget, frames, aOptions, aError);
   if (aError.Failed()) {
     return nullptr;
   }
 
   RefPtr<Animation> animation =
     Animation::Constructor(global, effect,
                            referenceElement->OwnerDoc()->Timeline(), aError);
   if (aError.Failed()) {