Don't run IntersectionObserver lifecycle in frames with dirty layout.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 4894 matching lines @@
 void FrameView::UpdateViewportIntersectionsForSubtree(
     DocumentLifecycle::LifecycleState target_state) {
   // TODO(dcheng): Since FrameViewBase tree updates are deferred, FrameViews
   // might still be in the FrameViewBase hierarchy even though the associated
   // Document is already detached. Investigate if this check and a similar check
   // in lifecycle updates are still needed when there are no more deferred
   // FrameViewBase updates: https://crbug.com/561683
   if (!GetFrame().GetDocument()->IsActive())
     return;
 
-  if (target_state == DocumentLifecycle::kPaintClean) {
+  if (target_state == DocumentLifecycle::kPaintClean && !NeedsLayout()) {
     RecordDeferredLoadingStats();
     // Notify javascript IntersectionObservers
     if (GetFrame().GetDocument()->GetIntersectionObserverController()) {
       GetFrame()
           .GetDocument()
           ->GetIntersectionObserverController()
           ->ComputeTrackedIntersectionObservations();
     }
   }
 
@@ skipping 467 matching lines @@
 void FrameView::SetAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   animation_host_ = std::move(host);
 }
 
 LayoutUnit FrameView::CaretWidth() const {
   return LayoutUnit(GetChromeClient()->WindowToViewportScalar(1));
 }
 
 }  // namespace blink