1 files changed, 29 insertions, 24 deletions

diff --git a/layout/base/nsRefreshDriver.cpp b/layout/base/nsRefreshDriver.cpp
index a5c2b1ded9..218d158a47 100644
--- a/layout/base/nsRefreshDriver.cpp
+++ b/layout/base/nsRefreshDriver.cpp
@@ -831,11 +831,11 @@ class VsyncRefreshDriverTimer : public RefreshDriverTimer {
     const TimeDuration previousRate = mVsyncRate;
     const TimeDuration rate = GetTimerRate();
 
-    hal::PerformanceHintSession* const performanceHintSession =
-        GetPerformanceHintSession();
-    if (performanceHintSession && rate != previousRate) {
-      performanceHintSession->UpdateTargetWorkDuration(
-          ContentChild::GetPerformanceHintTarget(rate));
+    if (rate != previousRate) {
+      if (auto* const performanceHintSession = GetPerformanceHintSession()) {
+        performanceHintSession->UpdateTargetWorkDuration(
+            ContentChild::GetPerformanceHintTarget(rate));
+      }
     }
 
     if (TimeDuration::FromMilliseconds(nsRefreshDriver::DefaultInterval()) >
@@ -862,7 +862,7 @@ class VsyncRefreshDriverTimer : public RefreshDriverTimer {
 
     TimeStamp tickEnd = TimeStamp::Now();
 
-    if (performanceHintSession) {
+    if (auto* const performanceHintSession = GetPerformanceHintSession()) {
       performanceHintSession->ReportActualWorkDuration(tickEnd - tickStart);
     }
 
@@ -1528,6 +1528,16 @@ void nsRefreshDriver::PostScrollEvent(mozilla::Runnable* aScrollEvent,
   }
 }
 
+void nsRefreshDriver::PostScrollEndEvent(mozilla::Runnable* aScrollEndEvent,
+                                         bool aDelayed) {
+  if (aDelayed) {
+    mDelayedScrollEndEvents.AppendElement(aScrollEndEvent);
+  } else {
+    mScrollEndEvents.AppendElement(aScrollEndEvent);
+    EnsureTimerStarted();
+  }
+}
+
 void nsRefreshDriver::DispatchScrollEvents() {
   // Scroll events are one-shot, so after running them we can drop them.
   // However, dispatching a scroll event can potentially cause more scroll
@@ -1539,6 +1549,13 @@ void nsRefreshDriver::DispatchScrollEvents() {
   }
 }
 
+void nsRefreshDriver::DispatchScrollEndEvents() {
+  ScrollEventArray events = std::move(mScrollEndEvents);
+  for (auto& event : events) {
+    event->Run();
+  }
+}
+
 void nsRefreshDriver::PostVisualViewportScrollEvent(
     VVPScrollEvent* aScrollEvent) {
   mVisualViewportScrollEvents.AppendElement(aScrollEvent);
@@ -1673,6 +1690,9 @@ void nsRefreshDriver::RunDelayedEventsSoon() {
   mScrollEvents.AppendElements(mDelayedScrollEvents);
   mDelayedScrollEvents.Clear();
 
+  mScrollEndEvents.AppendElements(mDelayedScrollEvents);
+  mDelayedScrollEndEvents.Clear();
+
   mResizeEventFlushObservers.AppendElements(mDelayedResizeEventFlushObservers);
   mDelayedResizeEventFlushObservers.Clear();
 
@@ -2008,7 +2028,7 @@ auto nsRefreshDriver::GetReasonsToTick() const -> TickReasons {
   if (!mVisualViewportResizeEvents.IsEmpty()) {
     reasons |= TickReasons::eHasVisualViewportResizeEvents;
   }
-  if (!mScrollEvents.IsEmpty()) {
+  if (!mScrollEvents.IsEmpty() || !mScrollEndEvents.IsEmpty()) {
     reasons |= TickReasons::eHasScrollEvents;
   }
   if (!mVisualViewportScrollEvents.IsEmpty()) {
@@ -2208,23 +2228,7 @@ void nsRefreshDriver::RunFullscreenSteps() {
 
 void nsRefreshDriver::UpdateIntersectionObservations(TimeStamp aNowTime) {
   AUTO_PROFILER_LABEL_RELEVANT_FOR_JS("Compute intersections", LAYOUT);
-
-  AutoTArray<RefPtr<Document>, 32> documents;
-
-  if (mPresContext->Document()->HasIntersectionObservers()) {
-    documents.AppendElement(mPresContext->Document());
-  }
-
-  mPresContext->Document()->CollectDescendantDocuments(
-      documents, [](const Document* document) -> bool {
-        return document->HasIntersectionObservers();
-      });
-
-  for (const auto& doc : documents) {
-    doc->UpdateIntersectionObservations(aNowTime);
-    doc->ScheduleIntersectionObserverNotification();
-  }
-
+  mPresContext->Document()->UpdateIntersections(aNowTime);
   mNeedToUpdateIntersectionObservations = false;
 }
 
@@ -2476,6 +2480,7 @@ bool nsRefreshDriver::TickObserverArray(uint32_t aIdx, TimeStamp aNowTime) {
     FlushAutoFocusDocuments();
     DispatchScrollEvents();
     DispatchVisualViewportScrollEvents();
+    DispatchScrollEndEvents();
     EvaluateMediaQueriesAndReportChanges();
     DispatchAnimationEvents();
     RunFullscreenSteps();