Backed out changeset ad5763672ad2 (bug 1194037) for Mochitest other bustage

--HG--
extra : rebase_source : 2b663ebe8f14dc1f449b492437977740f1dbd2c7

dom/animation/KeyframeEffect.h

@@ -168,20 +168,13 @@ struct AnimationProperty
   // **NOTE**: For CSS animations, we only bother setting mWinsInCascade
   // accurately for properties that we can animate on the compositor.
   // For other properties, we make it always be true.
-  // **NOTE 2**: This member is not included when comparing AnimationProperty
-  // objects for equality.
   bool mWinsInCascade;
 
   InfallibleTArray<AnimationPropertySegment> mSegments;
 
-  // NOTE: This operator does *not* compare the mWinsInCascade member.
-  // This is because AnimationProperty objects are compared when recreating
-  // CSS animations to determine if mutation observer change records need to
-  // be created or not. However, at the point when these objects are compared
-  // the mWinsInCascade will not have been set on the new objects so we ignore
-  // this member to avoid generating spurious change records.
   bool operator==(const AnimationProperty& aOther) const {
     return mProperty == aOther.mProperty &&
+           mWinsInCascade == aOther.mWinsInCascade &&
            mSegments == aOther.mSegments;
   }
   bool operator!=(const AnimationProperty& aOther) const {