Tie scroll anchoring adjustments to frame lifecycle instead of layout.

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

Index: third_party/WebKit/Source/core/frame/FrameView.h
diff --git a/third_party/WebKit/Source/core/frame/FrameView.h b/third_party/WebKit/Source/core/frame/FrameView.h
index 2254b992c0355836176f687ca67616b69d50d73a..d58707f1d1f56e8980243862172570da04a694c5 100644
--- a/third_party/WebKit/Source/core/frame/FrameView.h
+++ b/third_party/WebKit/Source/core/frame/FrameView.h
@@ -728,6 +728,8 @@ class CORE_EXPORT FrameView final
   ScrollAnchor* scrollAnchor() override { return &m_scrollAnchor; }
   void clearScrollAnchor();
   bool shouldPerformScrollAnchoring() const override;
+  void enqueueScrollAnchoringAdjustment(ScrollableArea*);
+  void performScrollAnchoringAdjustments();
 
   // For PaintInvalidator temporarily. TODO(wangxianzhu): Move into
   // PaintInvalidator.
@@ -1076,6 +1078,9 @@ class CORE_EXPORT FrameView final
   DocumentLifecycle::LifecycleState m_currentUpdateLifecyclePhasesTargetState;
 
   ScrollAnchor m_scrollAnchor;
+  using AnchoringAdjustmentQueue =
+      HeapLinkedHashSet<WeakMember<ScrollableArea>>;
+  AnchoringAdjustmentQueue m_anchoringAdjustmentQueue;
 
   // ScrollbarManager holds the Scrollbar instances.
   ScrollbarManager m_scrollbarManager;