--- a/dom/animation/ComputedTimingFunction.h
+++ b/dom/animation/ComputedTimingFunction.h
@@ -75,16 +75,30 @@ public:
            (HasSpline() ?
             mTimingFunction == aOther.mTimingFunction :
             mStepsOrFrames == aOther.mStepsOrFrames);
   }
   bool operator!=(const ComputedTimingFunction& aOther) const
   {
     return !(*this == aOther);
   }
+  bool operator==(const nsTimingFunction& aOther) const
+  {
+    return mType == aOther.mType &&
+           (HasSpline()
+            ? mTimingFunction.X1() == aOther.mFunc.mX1 &&
+              mTimingFunction.Y1() == aOther.mFunc.mY1 &&
+              mTimingFunction.X2() == aOther.mFunc.mX2 &&
+              mTimingFunction.Y2() == aOther.mFunc.mY2
+            : mStepsOrFrames == aOther.mStepsOrFrames);
+  }
+  bool operator!=(const nsTimingFunction& aOther) const
+  {
+    return !(*this == aOther);
+  }
   int32_t Compare(const ComputedTimingFunction& aRhs) const;
   void AppendToString(nsAString& aResult) const;
 
   static double GetPortion(const Maybe<ComputedTimingFunction>& aFunction,
                            double aPortion,
                            BeforeFlag aBeforeFlag)
   {
     return aFunction ? aFunction->GetValue(aPortion, aBeforeFlag) : aPortion;
@@ -100,11 +114,28 @@ private:
     : mType(aType)
     , mStepsOrFrames(aStepsOrFrames) { }
 
   nsTimingFunction::Type mType = nsTimingFunction::Type::Linear;
   nsSMILKeySpline mTimingFunction;
   uint32_t mStepsOrFrames;
 };
 
+inline bool
+operator==(const Maybe<ComputedTimingFunction>& aLHS,
+           const nsTimingFunction& aRHS)
+{
+  if (aLHS.isNothing()) {
+    return aRHS.mType == nsTimingFunction::Type::Linear;
+  }
+  return aLHS.value() == aRHS;
+}
+
+inline bool
+operator!=(const Maybe<ComputedTimingFunction>& aLHS,
+           const nsTimingFunction& aRHS)
+{
+  return !(aLHS == aRHS);
+}
+
 } // namespace mozilla
 
 #endif // mozilla_ComputedTimingFunction_h