2 files changed, 13 insertions, 4 deletions
diff --git a/dom/animation/Animation.cpp b/dom/animation/Animation.cpp
index 242a0c6d6..bd318f79e 100644
--- a/dom/animation/Animation.cpp
+++ b/dom/animation/Animation.cpp
@@ -787,12 +787,21 @@ Animation::CancelNoUpdate()
   mHoldTime.SetNull();
   mStartTime.SetNull();
 
-  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
-
   if (mTimeline) {
     mTimeline->RemoveAnimation(this);
   }
   MaybeQueueCancelEvent(activeTime);
+
+  // When an animation is cancelled it no longer needs further ticks from the
+  // timeline. However, if we queued a cancel event and this was the last
+  // animation attached to the timeline, the timeline will stop observing the
+  // refresh driver and there may be no subsequent refresh driver tick for
+  // dispatching the queued event.
+  //
+  // By calling UpdateTiming *after* removing ourselves from our timeline, we
+  // ensure the timeline will register with the refresh driver for at least one
+  // more tick.
+  UpdateTiming(SeekFlag::NoSeek, SyncNotifyFlag::Async);
 }
 
 void
diff --git a/dom/animation/ComputedTiming.h b/dom/animation/ComputedTiming.h
index addf15865..525d59d23 100644
--- a/dom/animation/ComputedTiming.h
+++ b/dom/animation/ComputedTiming.h
@@ -64,12 +64,12 @@ struct ComputedTiming
   }
 
   enum class AnimationPhase {
-    Null,   // Not sampled (null sample time)
+    Idle,   // Not sampled (null sample time)
     Before, // Sampled prior to the start of the active interval
     Active, // Sampled within the active interval
     After   // Sampled after (or at) the end of the active interval
   };
-  AnimationPhase      mPhase = AnimationPhase::Null;
+  AnimationPhase      mPhase = AnimationPhase::Idle;
 
   ComputedTimingFunction::BeforeFlag mBeforeFlag =
     ComputedTimingFunction::BeforeFlag::Unset;