1 files changed, 16 insertions, 11 deletions
diff --git a/layout/style/nsAnimationManager.h b/layout/style/nsAnimationManager.h
index abe3aeeb88..d838d090a9 100644
--- a/layout/style/nsAnimationManager.h
+++ b/layout/style/nsAnimationManager.h
@@ -76,7 +76,8 @@ public:
     , mIsStylePaused(false)
     , mPauseShouldStick(false)
     , mNeedsNewAnimationIndexWhenRun(false)
-    , mPreviousPhaseOrIteration(PREVIOUS_PHASE_BEFORE)
+    , mPreviousPhase(ComputedTiming::AnimationPhase::Idle)
+    , mPreviousIteration(0)
   {
     // We might need to drop this assertion once we add a script-accessible
     // constructor but for animations generated from CSS markup the
@@ -109,8 +110,6 @@ public:
   void PauseFromStyle();
   void CancelFromStyle() override
   {
-    mOwningElement = OwningElementRef();
-
     // When an animation is disassociated with style it enters an odd state
     // where its composite order is undefined until it first transitions
     // out of the idle state.
@@ -125,10 +124,15 @@ public:
     mNeedsNewAnimationIndexWhenRun = true;
 
     Animation::CancelFromStyle();
+
+    // We need to do this *after* calling CancelFromStyle() since
+    // CancelFromStyle might synchronously trigger a cancel event for which
+    // we need an owning element to target the event at.
+    mOwningElement = OwningElementRef();
   }
 
   void Tick() override;
-  void QueueEvents();
+  void QueueEvents(StickyTimeDuration aActiveTime = StickyTimeDuration());
 
   bool IsStylePaused() const { return mIsStylePaused; }
 
@@ -157,6 +161,10 @@ public:
   // reflect changes to that markup.
   bool IsTiedToMarkup() const { return mOwningElement.IsSet(); }
 
+  void MaybeQueueCancelEvent(StickyTimeDuration aActiveTime) override {
+    QueueEvents(aActiveTime);
+  }
+
 protected:
   virtual ~CSSAnimation()
   {
@@ -257,13 +265,10 @@ protected:
   // its animation index should be updated.
   bool mNeedsNewAnimationIndexWhenRun;
 
-  enum {
-    PREVIOUS_PHASE_BEFORE = uint64_t(-1),
-    PREVIOUS_PHASE_AFTER = uint64_t(-2)
-  };
-  // One of the PREVIOUS_PHASE_* constants, or an integer for the iteration
-  // whose start we last notified on.
-  uint64_t mPreviousPhaseOrIteration;
+  // Phase and current iteration from the previous time we queued events.
+  // This is used to determine what new events to dispatch.
+  ComputedTiming::AnimationPhase mPreviousPhase;
+  uint64_t mPreviousIteration;
 };
 
 } /* namespace dom */