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 4889 matching lines @@
   // 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) {
     RecordDeferredLoadingStats();
-    // Notify javascript IntersectionObservers
-    if (GetFrame().GetDocument()->GetIntersectionObserverController()) {
-      GetFrame()
-          .GetDocument()
-          ->GetIntersectionObserverController()
-          ->ComputeTrackedIntersectionObservations();
+    if (!NeedsLayout()) {
+      // Notify javascript IntersectionObservers
+      if (GetFrame().GetDocument()->GetIntersectionObserverController()) {
+        GetFrame()
+            .GetDocument()
+            ->GetIntersectionObserverController()
+            ->ComputeTrackedIntersectionObservations();
+      }
     }
   }
 
   // Don't throttle display:none frames (see updateRenderThrottlingStatus).
   HTMLFrameOwnerElement* owner_element = frame_->DeprecatedLocalOwner();
   if (hidden_for_throttling_ && owner_element &&
       !owner_element->GetLayoutObject()) {
     // No need to notify children because descendants of display:none frames
     // should remain throttled.
     UpdateRenderThrottlingStatus(hidden_for_throttling_, subtree_throttled_,
@@ skipping 460 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