--- a/layout/style/nsAnimationManager.h
+++ b/layout/style/nsAnimationManager.h
@@ -27,17 +27,16 @@ namespace css {
 class Declaration;
 } /* namespace css */
 namespace dom {
 class KeyframeEffectReadOnly;
 class Promise;
 } /* namespace dom */
 
 class GeckoComputedStyle;
-class ComputedStyle;
 enum class CSSPseudoElementType : uint8_t;
 struct NonOwningAnimationTarget;
 
 namespace dom {
 
 class CSSAnimation final : public Animation
 {
 public:

--- a/layout/style/nsTransitionManager.h
+++ b/layout/style/nsTransitionManager.h
@@ -21,17 +21,16 @@ class nsPresContext;
 class nsCSSPropertyIDSet;
 
 namespace mozilla {
 class ComputedStyle;
 enum class CSSPseudoElementType : uint8_t;
 class GeckoComputedStyle;
 struct Keyframe;
 struct StyleTransition;
-class ComputedStyle;
 } // namespace mozilla
 
 /*****************************************************************************
  * Per-Element data                                                          *
  *****************************************************************************/
 
 namespace mozilla {