--- a/dom/animation/AnimationUtils.cpp
+++ b/dom/animation/AnimationUtils.cpp
@@ -1,16 +1,17 @@
 /* -*- 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 "AnimationUtils.h"
 
+#include "nsContentUtils.h" // For nsContentUtils::IsCallerChrome
 #include "nsDebug.h"
 #include "nsIAtom.h"
 #include "nsIContent.h"
 #include "nsIDocument.h"
 #include "nsGlobalWindow.h"
 #include "nsString.h"
 #include "xpcpublic.h" // For xpc::NativeGlobal
 #include "mozilla/Preferences.h"
@@ -58,23 +59,23 @@ AnimationUtils::IsOffscreenThrottlingEna
     Preferences::AddBoolVarCache(&sOffscreenThrottlingEnabled,
                                  "dom.animations.offscreen-throttling");
   }
 
   return sOffscreenThrottlingEnabled;
 }
 
 /* static */ bool
-AnimationUtils::IsCoreAPIEnabled()
+AnimationUtils::IsCoreAPIEnabledForCaller()
 {
   static bool sCoreAPIEnabled;
   static bool sPrefCached = false;
 
   if (!sPrefCached) {
     sPrefCached = true;
     Preferences::AddBoolVarCache(&sCoreAPIEnabled,
                                  "dom.animations-api.core.enabled");
   }
 
-  return sCoreAPIEnabled;
+  return sCoreAPIEnabled || nsContentUtils::IsCallerChrome();
 }
 
 } // namespace mozilla

--- a/dom/animation/AnimationUtils.h
+++ b/dom/animation/AnimationUtils.h
@@ -58,17 +58,17 @@ public:
   /**
    * Checks if offscreen animation throttling is enabled.
    */
   static bool
   IsOffscreenThrottlingEnabled();
 
   /**
    * Returns true if the preference to enable the core Web Animations API is
-   * true.
+   * true or the caller is chrome.
    */
   static bool
-  IsCoreAPIEnabled();
+  IsCoreAPIEnabledForCaller();
 };
 
 } // namespace mozilla
 
 #endif

--- a/dom/animation/KeyframeEffect.cpp
+++ b/dom/animation/KeyframeEffect.cpp
@@ -127,17 +127,17 @@ KeyframeEffect::SetTarget(const Nullable
 }
 
 void
 KeyframeEffect::SetIterationComposite(
   const IterationCompositeOperation& aIterationComposite)
 {
   // Ignore iterationComposite if the Web Animations API is not enabled,
   // then the default value 'Replace' will be used.
-  if (!AnimationUtils::IsCoreAPIEnabled()) {
+  if (!AnimationUtils::IsCoreAPIEnabledForCaller()) {
     return;
   }
 
   if (mEffectOptions.mIterationComposite == aIterationComposite) {
     return;
   }
 
   if (mAnimation && mAnimation->IsRelevant()) {

--- a/dom/animation/KeyframeEffectParams.cpp
+++ b/dom/animation/KeyframeEffectParams.cpp
@@ -110,17 +110,17 @@ KeyframeEffectParams::ParseSpacing(const
                                    nsCSSPropertyID& aPacedProperty,
                                    nsAString& aInvalidPacedProperty,
                                    ErrorResult& aRv)
 {
   aInvalidPacedProperty.Truncate();
 
   // Ignore spacing if the core API is not enabled since it is not yet ready to
   // ship.
-  if (!AnimationUtils::IsCoreAPIEnabled()) {
+  if (!AnimationUtils::IsCoreAPIEnabledForCaller()) {
     aSpacingMode = SpacingMode::distribute;
     return;
   }
 
   // Parse spacing.
   // distribute | paced({ident})
   // https://w3c.github.io/web-animations/#dom-keyframeeffectreadonly-spacing
   // 1. distribute spacing.

--- a/dom/animation/KeyframeEffectReadOnly.cpp
+++ b/dom/animation/KeyframeEffectReadOnly.cpp
@@ -507,17 +507,17 @@ KeyframeEffectParamsFromUnion(const Opti
       KeyframeEffectOptionsFromUnion(aOptions);
     KeyframeEffectParams::ParseSpacing(options.mSpacing,
                                        result.mSpacingMode,
                                        result.mPacedProperty,
                                        aInvalidPacedProperty,
                                        aRv);
     // Ignore iterationComposite if the Web Animations API is not enabled,
     // then the default value 'Replace' will be used.
-    if (AnimationUtils::IsCoreAPIEnabled()) {
+    if (AnimationUtils::IsCoreAPIEnabledForCaller()) {
       result.mIterationComposite = options.mIterationComposite;
     }
   }
   return result;
 }
 
 /* static */ Maybe<OwningAnimationTarget>
 KeyframeEffectReadOnly::ConvertTarget(