FrameView shouldn't apply scroll anchoring when root layer scrolling is enabled

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 736 matching lines @@
     // but the scroll origin *did* change, we still need to notify the scrollbars to
     // update their dimensions.
 
     if (DelayScrollPositionClampScope::clampingIsDelayed()) {
         DelayScrollPositionClampScope::setNeedsClamp(this);
         return;
     }
 
     DoublePoint clamped = clampScrollPosition(scrollPositionDouble());
     // Restore before clamping because clamping clears the scroll anchor.
-    if (clamped != scrollPositionDouble() && shouldPerformScrollAnchoring() && m_scrollAnchor.hasScroller()) {
+    if (clamped != scrollPositionDouble() && shouldPerformScrollAnchoring()) {
         m_scrollAnchor.restore();
         clamped = clampScrollPosition(scrollPositionDouble());
     }
     if (clamped != scrollPositionDouble() || scrollOriginChanged())
         ScrollableArea::setScrollPosition(clamped, ProgrammaticScroll);
 
     setNeedsScrollPositionClamp(false);
     resetScrollOriginChanged();
     m_scrollbarManager.destroyDetachedScrollbars();
 }
 
+bool PaintLayerScrollableArea::shouldPerformScrollAnchoring() const
+{
+    return RuntimeEnabledFeatures::scrollAnchoringEnabled()
+        && m_scrollAnchor.hasScroller()
+        && layoutBox()->style()->overflowAnchor() != AnchorNone;
+}
+
 ScrollBehavior PaintLayerScrollableArea::scrollBehaviorStyle() const
 {
     return box().style()->getScrollBehavior();
 }
 
 bool PaintLayerScrollableArea::hasHorizontalOverflow() const
 {
     // TODO(szager): Make the algorithm for adding/subtracting overflow:auto
     // scrollbars memoryless (crbug.com/625300).  This clientWidth hack will
     // prevent the spurious horizontal scrollbar, but it can cause a converse
@@ skipping 972 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollPositionClampScope::clampScrollableAreas()
 {
     for (auto& scrollableArea : *s_needsClamp)
         scrollableArea->clampScrollPositionsAfterLayout();
     delete s_needsClamp;
     s_needsClamp = nullptr;
 }
 
 } // namespace blink