--- a/dom/animation/AnimationEffectReadOnly.cpp
+++ b/dom/animation/AnimationEffectReadOnly.cpp
@@ -3,17 +3,17 @@
 /* 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/. */
 
 #include "mozilla/dom/AnimationEffectReadOnly.h"
 #include "mozilla/dom/AnimationEffectReadOnlyBinding.h"
 
 #include "mozilla/dom/Animation.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/AnimationUtils.h"
 #include "mozilla/FloatingPoint.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(AnimationEffectReadOnly)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AnimationEffectReadOnly)

--- a/dom/animation/AnimationEffectTiming.cpp
+++ b/dom/animation/AnimationEffectTiming.cpp
@@ -3,17 +3,17 @@
 /* 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/. */
 
 #include "mozilla/dom/AnimationEffectTiming.h"
 
 #include "mozilla/dom/AnimatableBinding.h"
 #include "mozilla/dom/AnimationEffectTimingBinding.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/TimingParams.h"
 #include "nsAString.h"
 
 namespace mozilla {
 namespace dom {
 
 JSObject*
 AnimationEffectTiming::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)

--- a/dom/animation/AnimationUtils.cpp
+++ b/dom/animation/AnimationUtils.cpp
@@ -9,17 +9,17 @@
 #include "nsDebug.h"
 #include "nsAtom.h"
 #include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsGlobalWindow.h"
 #include "nsString.h"
 #include "xpcpublic.h" // For xpc::NativeGlobal
 #include "mozilla/EffectSet.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/Preferences.h"
 
 namespace mozilla {
 
 /* static */ void
 AnimationUtils::LogAsyncAnimationFailure(nsCString& aMessage,
                                          const nsIContent* aContent)
 {

--- a/dom/animation/EffectCompositor.cpp
+++ b/dom/animation/EffectCompositor.cpp
@@ -6,17 +6,17 @@
 
 #include "EffectCompositor.h"
 
 #include <bitset>
 #include <initializer_list>
 
 #include "mozilla/dom/Animation.h"
 #include "mozilla/dom/Element.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/AnimationComparator.h"
 #include "mozilla/AnimationPerformanceWarning.h"
 #include "mozilla/AnimationTarget.h"
 #include "mozilla/AnimationUtils.h"
 #include "mozilla/AutoRestore.h"
 #include "mozilla/ComputedStyleInlines.h"
 #include "mozilla/EffectSet.h"
 #include "mozilla/LayerAnimationInfo.h"

--- a/dom/animation/EffectSet.h
+++ b/dom/animation/EffectSet.h
@@ -6,17 +6,17 @@
 
 #ifndef mozilla_EffectSet_h
 #define mozilla_EffectSet_h
 
 #include "mozilla/DebugOnly.h"
 #include "mozilla/EffectCompositor.h"
 #include "mozilla/EnumeratedArray.h"
 #include "mozilla/TimeStamp.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "nsHashKeys.h" // For nsPtrHashKey
 #include "nsTHashtable.h" // For nsTHashtable
 
 class nsPresContext;
 
 namespace mozilla {
 
 namespace dom {

rename from dom/animation/KeyframeEffectReadOnly.cpp
rename to dom/animation/KeyframeEffect.cpp
--- a/dom/animation/KeyframeEffectReadOnly.cpp
+++ b/dom/animation/KeyframeEffect.cpp
@@ -1,15 +1,15 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* 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/. */
 
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 
 #include "FrameLayerBuilder.h"
 #include "mozilla/dom/Animation.h"
 #include "mozilla/dom/KeyframeAnimationOptionsBinding.h"
   // For UnrestrictedDoubleOrKeyframeAnimationOptions;
 #include "mozilla/dom/CSSPseudoElement.h"
 #include "mozilla/dom/KeyframeEffectBinding.h"
 #include "mozilla/AnimationUtils.h"

rename from dom/animation/KeyframeEffectReadOnly.h
rename to dom/animation/KeyframeEffect.h
--- a/dom/animation/KeyframeEffectReadOnly.h
+++ b/dom/animation/KeyframeEffect.h
@@ -1,16 +1,16 @@
 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
 /* 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/. */
 
-#ifndef mozilla_dom_KeyframeEffectReadOnly_h
-#define mozilla_dom_KeyframeEffectReadOnly_h
+#ifndef mozilla_dom_KeyframeEffect_h
+#define mozilla_dom_KeyframeEffect_h
 
 #include "nsChangeHint.h"
 #include "nsCSSPropertyID.h"
 #include "nsCSSPropertyIDSet.h"
 #include "nsCSSValue.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsRefPtrHashtable.h"
 #include "nsTArray.h"
@@ -486,9 +486,9 @@ public:
               JS::Handle<JSObject*> aKeyframes,
               const UnrestrictedDoubleOrKeyframeAnimationOptions& aOptions,
               ErrorResult& aRv);
 };
 
 } // namespace dom
 } // namespace mozilla
 
-#endif // mozilla_dom_KeyframeEffectReadOnly_h
+#endif // mozilla_dom_KeyframeEffect_h

--- a/dom/animation/KeyframeUtils.cpp
+++ b/dom/animation/KeyframeUtils.cpp
@@ -13,17 +13,17 @@
 #include "mozilla/ServoBindings.h"
 #include "mozilla/ServoBindingTypes.h"
 #include "mozilla/ServoCSSParser.h"
 #include "mozilla/StyleAnimationValue.h"
 #include "mozilla/TimingParams.h"
 #include "mozilla/dom/BaseKeyframeTypesBinding.h" // For FastBaseKeyframe etc.
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/KeyframeEffectBinding.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h" // For PropertyValuesPair etc.
+#include "mozilla/dom/KeyframeEffect.h" // For PropertyValuesPair etc.
 #include "mozilla/dom/Nullable.h"
 #include "jsapi.h" // For ForOfIterator etc.
 #include "nsClassHashtable.h"
 #include "nsContentUtils.h" // For GetContextForContent, and
                             // AnimationsAPICoreEnabled
 #include "nsCSSPropertyIDSet.h"
 #include "nsCSSProps.h"
 #include "nsCSSPseudoElements.h" // For CSSPseudoElementType

--- a/dom/animation/moz.build
+++ b/dom/animation/moz.build
@@ -13,17 +13,17 @@ MOCHITEST_CHROME_MANIFESTS += ['test/chr
 EXPORTS.mozilla.dom += [
     'Animation.h',
     'AnimationEffectReadOnly.h',
     'AnimationEffectTiming.h',
     'AnimationEffectTimingReadOnly.h',
     'AnimationTimeline.h',
     'CSSPseudoElement.h',
     'DocumentTimeline.h',
-    'KeyframeEffectReadOnly.h',
+    'KeyframeEffect.h',
 ]
 
 EXPORTS.mozilla += [
     'AnimationComparator.h',
     'AnimationEventDispatcher.h',
     'AnimationPerformanceWarning.h',
     'AnimationPropertySegment.h',
     'AnimationTarget.h',
@@ -49,17 +49,17 @@ UNIFIED_SOURCES += [
     'AnimationPerformanceWarning.cpp',
     'AnimationTimeline.cpp',
     'AnimationUtils.cpp',
     'ComputedTimingFunction.cpp',
     'CSSPseudoElement.cpp',
     'DocumentTimeline.cpp',
     'EffectCompositor.cpp',
     'EffectSet.cpp',
-    'KeyframeEffectReadOnly.cpp',
+    'KeyframeEffect.cpp',
     'KeyframeUtils.cpp',
     'PendingAnimationTracker.cpp',
     'TimingParams.cpp',
 ]
 
 LOCAL_INCLUDES += [
     '/dom/base',
     '/layout/base',

--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -132,17 +132,17 @@
 #include "nsXBLService.h"
 #include "nsITextControlElement.h"
 #include "nsITextControlFrame.h"
 #include "nsISupportsImpl.h"
 #include "mozilla/dom/CSSPseudoElement.h"
 #include "mozilla/dom/DocumentFragment.h"
 #include "mozilla/dom/ElementBinding.h"
 #include "mozilla/dom/KeyframeEffectBinding.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/dom/MouseEventBinding.h"
 #include "mozilla/dom/WindowBinding.h"
 #include "mozilla/dom/VRDisplay.h"
 #include "mozilla/IntegerPrintfMacros.h"
 #include "mozilla/Preferences.h"
 #include "nsComputedDOMStyle.h"
 #include "nsDOMStringMap.h"
 #include "DOMIntersectionObserver.h"

--- a/dom/base/nsDOMMutationObserver.cpp
+++ b/dom/base/nsDOMMutationObserver.cpp
@@ -6,17 +6,17 @@
 
 #include "nsDOMMutationObserver.h"
 
 #include "mozilla/AnimationTarget.h"
 #include "mozilla/Maybe.h"
 #include "mozilla/OwningNonNull.h"
 
 #include "mozilla/dom/Animation.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/dom/DocGroup.h"
 
 #include "nsContentUtils.h"
 #include "nsCSSPseudoElements.h"
 #include "nsError.h"
 #include "nsIScriptGlobalObject.h"
 #include "nsServiceManagerUtils.h"
 #include "nsTextFragment.h"

--- a/dom/base/nsNodeUtils.cpp
+++ b/dom/base/nsNodeUtils.cpp
@@ -25,17 +25,17 @@
 #include "nsBindingManager.h"
 #include "nsGenericHTMLElement.h"
 #include "mozilla/AnimationTarget.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/ErrorResult.h"
 #include "mozilla/dom/Animation.h"
 #include "mozilla/dom/HTMLImageElement.h"
 #include "mozilla/dom/HTMLMediaElement.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "nsWrapperCacheInlines.h"
 #include "nsObjectLoadingContent.h"
 #include "nsDOMMutationObserver.h"
 #include "mozilla/dom/BindingUtils.h"
 #include "mozilla/dom/HTMLTemplateElement.h"
 #include "mozilla/dom/ShadowRoot.h"
 
 using namespace mozilla;

--- a/dom/webidl/KeyframeEffect.webidl
+++ b/dom/webidl/KeyframeEffect.webidl
@@ -19,16 +19,17 @@ dictionary KeyframeEffectOptions : Anima
   IterationCompositeOperation iterationComposite = "replace";
   CompositeOperation          composite = "replace";
 };
 
 // KeyframeEffectReadOnly should run in the caller's compartment to do custom
 // processing on the `keyframes` object.
 [Func="nsDocument::IsWebAnimationsEnabled",
  RunConstructorInCallerCompartment,
+ HeaderFile="mozilla/dom/KeyframeEffect.h",
  Constructor ((Element or CSSPseudoElement)? target,
               object? keyframes,
               optional (unrestricted double or KeyframeEffectOptions) options),
  Constructor (KeyframeEffectReadOnly source)]
 interface KeyframeEffectReadOnly : AnimationEffectReadOnly {
   attribute (Element or CSSPseudoElement)?  target;
   [NeedsCallerType]
   attribute IterationCompositeOperation iterationComposite;
@@ -57,17 +58,16 @@ dictionary AnimationPropertyDetails {
 partial interface KeyframeEffectReadOnly {
   [ChromeOnly, Throws] sequence<AnimationPropertyDetails> getProperties();
 };
 
 // KeyframeEffect should run in the caller's compartment to do custom
 // processing on the `keyframes` object.
 [Func="nsDocument::IsWebAnimationsEnabled",
  RunConstructorInCallerCompartment,
- HeaderFile="mozilla/dom/KeyframeEffectReadOnly.h",
  Constructor ((Element or CSSPseudoElement)? target,
               object? keyframes,
               optional (unrestricted double or KeyframeEffectOptions) options),
  Constructor (KeyframeEffectReadOnly source)]
 interface KeyframeEffect : KeyframeEffectReadOnly {
   [Throws]
   void setKeyframes (object? keyframes);
 };

--- a/gfx/layers/AnimationHelper.cpp
+++ b/gfx/layers/AnimationHelper.cpp
@@ -3,17 +3,17 @@
 /* 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/. */
 
 #include "AnimationHelper.h"
 #include "mozilla/ComputedTimingFunction.h" // for ComputedTimingFunction
 #include "mozilla/dom/AnimationEffectReadOnlyBinding.h" // for dom::FillMode
 #include "mozilla/dom/KeyframeEffectBinding.h" // for dom::IterationComposite
-#include "mozilla/dom/KeyframeEffectReadOnly.h" // for dom::KeyFrameEffectReadOnly
+#include "mozilla/dom/KeyframeEffect.h" // for dom::KeyFrameEffectReadOnly
 #include "mozilla/dom/Nullable.h" // for dom::Nullable
 #include "mozilla/layers/CompositorThread.h" // for CompositorThreadHolder
 #include "mozilla/layers/LayerAnimationUtils.h" // for TimingFunctionToComputedTimingFunction
 #include "mozilla/ServoBindings.h" // for Servo_ComposeAnimationSegment, etc
 #include "mozilla/StyleAnimationValue.h" // for StyleAnimationValue, etc
 #include "nsDeviceContext.h"            // for AppUnitsPerCSSPixel
 #include "nsDisplayList.h"              // for nsDisplayTransform, etc
 

--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -68,17 +68,17 @@
 #include <algorithm>
 #include <limits>
 #include "mozilla/dom/AnonymousContent.h"
 #include "mozilla/dom/HTMLMediaElementBinding.h"
 #include "mozilla/dom/HTMLVideoElement.h"
 #include "mozilla/dom/HTMLImageElement.h"
 #include "mozilla/dom/DOMRect.h"
 #include "mozilla/dom/DOMStringList.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/layers/APZCCallbackHelper.h"
 #include "imgIRequest.h"
 #include "nsIImageLoadingContent.h"
 #include "nsCOMPtr.h"
 #include "nsCSSProps.h"
 #include "nsListControlFrame.h"
 #include "mozilla/dom/Element.h"
 #include "nsCanvasFrame.h"

--- a/layout/painting/nsDisplayList.cpp
+++ b/layout/painting/nsDisplayList.cpp
@@ -14,17 +14,17 @@
 
 #include <stdint.h>
 #include <algorithm>
 #include <limits>
 
 #include "gfxContext.h"
 #include "gfxUtils.h"
 #include "mozilla/dom/TabChild.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "mozilla/dom/Selection.h"
 #include "mozilla/gfx/2D.h"
 #include "mozilla/layers/PLayerTransaction.h"
 #include "nsCSSRendering.h"
 #include "nsCSSRenderingGradients.h"
 #include "nsISelectionController.h"
 #include "nsIPresShell.h"
 #include "nsRegion.h"

--- a/layout/style/nsAnimationManager.cpp
+++ b/layout/style/nsAnimationManager.cpp
@@ -12,17 +12,17 @@
 #include "mozilla/AnimationTarget.h"
 #include "mozilla/EffectCompositor.h"
 #include "mozilla/EffectSet.h"
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/ServoStyleSet.h"
 #include "mozilla/StyleAnimationValue.h"
 #include "mozilla/dom/AnimationEffectReadOnly.h"
 #include "mozilla/dom/DocumentTimeline.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 
 #include "nsPresContext.h"
 #include "nsStyleChangeList.h"
 #include "nsContentUtils.h"
 #include "nsLayoutUtils.h"
 #include "nsIFrame.h"
 #include "nsIDocument.h"
 #include "nsDOMMutationObserver.h"

--- a/layout/style/nsTransitionManager.h
+++ b/layout/style/nsTransitionManager.h
@@ -7,17 +7,17 @@
 /* Code to start and animate CSS transitions. */
 
 #ifndef nsTransitionManager_h_
 #define nsTransitionManager_h_
 
 #include "mozilla/ComputedTiming.h"
 #include "mozilla/EffectCompositor.h" // For EffectCompositor::CascadeLevel
 #include "mozilla/dom/Animation.h"
-#include "mozilla/dom/KeyframeEffectReadOnly.h"
+#include "mozilla/dom/KeyframeEffect.h"
 #include "AnimationCommon.h"
 #include "nsISupportsImpl.h"
 
 class nsIGlobalObject;
 class nsPresContext;
 class nsCSSPropertyIDSet;
 
 namespace mozilla {