Clamp scroll offset after overflow reclacs that are not layout inducing

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>
@@ skipping 766 matching lines @@
     }
   }
 
   if (!scrollbarsAreFrozen && hasOverlayScrollbars()) {
     if (!scrollSize(HorizontalScrollbar))
       setHasHorizontalScrollbar(false);
     if (!scrollSize(VerticalScrollbar))
       setHasVerticalScrollbar(false);
   }
 
-  clampScrollOffsetsAfterLayout();
+  clampScrollOffsetAfterOverflowChange();
 
   if (!scrollbarsAreFrozen) {
     updateScrollableAreaSet(hasScrollableHorizontalOverflow() ||
                             hasScrollableVerticalOverflow());
   }
 
   DisableCompositingQueryAsserts disabler;
   positionOverflowControls();
 }
 
-void PaintLayerScrollableArea::clampScrollOffsetsAfterLayout() {
+void PaintLayerScrollableArea::clampScrollOffsetAfterOverflowChange() {
   // If a vertical scrollbar was removed, the min/max scroll offsets may have
   // changed, so the scroll offsets needs to be clamped.  If the scroll offset
   // did not change, but the scroll origin *did* change, we still need to notify
   // the scrollbars to update their dimensions.
 
   if (DelayScrollOffsetClampScope::clampingIsDelayed()) {
     DelayScrollOffsetClampScope::setNeedsClamp(this);
     return;
   }
 
@@ skipping 174 matching lines @@
   bool horizontalScrollbarShouldChange =
       needsHorizontalScrollbar != hasHorizontalScrollbar();
   bool verticalScrollbarShouldChange =
       needsVerticalScrollbar != hasVerticalScrollbar();
 
   if ((box().hasAutoHorizontalScrollbar() && horizontalScrollbarShouldChange) ||
       (box().hasAutoVerticalScrollbar() && verticalScrollbarShouldChange)) {
     box().setNeedsLayoutAndFullPaintInvalidation(
         LayoutInvalidationReason::Unknown);
   }
+
+  clampScrollOffsetAfterOverflowChange();
 }
 
 IntRect PaintLayerScrollableArea::rectForHorizontalScrollbar(
     const IntRect& borderBoxRect) const {
   if (!hasHorizontalScrollbar())
     return IntRect();
 
   const IntRect& scrollCorner = scrollCornerRect();
 
   return IntRect(horizontalScrollbarStart(borderBoxRect.x()),
@@ skipping 993 matching lines @@
     PaintLayerScrollableArea* scrollableArea) {
   if (!scrollableArea->needsScrollOffsetClamp()) {
     scrollableArea->setNeedsScrollOffsetClamp(true);
     s_needsClamp->append(scrollableArea);
   }
 }
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     clampScrollableAreas() {
   for (auto& scrollableArea : *s_needsClamp)
-    scrollableArea->clampScrollOffsetsAfterLayout();
+    scrollableArea->clampScrollOffsetAfterOverflowChange();
   delete s_needsClamp;
   s_needsClamp = nullptr;
 }
 
 }  // namespace blink