Replace adjustment of previous visual rects on scroll with normal paint invalidation

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 354 matching lines @@
   return (orientation == HorizontalScrollbar) ? scrollDimensions.width()
                                               : scrollDimensions.height();
 }
 
 void PaintLayerScrollableArea::updateScrollOffset(const ScrollOffset& newOffset,
                                                   ScrollType scrollType) {
   if (getScrollOffset() == newOffset)
     return;
 
   showOverlayScrollbars();
-  ScrollOffset scrollDelta = getScrollOffset() - newOffset;
   m_scrollOffset = newOffset;
 
   LocalFrame* frame = box().frame();
   DCHECK(frame);
 
   FrameView* frameView = box().frameView();
 
   TRACE_EVENT1("devtools.timeline", "ScrollLayer", "data",
                InspectorScrollLayerEvent::data(&box()));
 
   // FIXME(420741): Resolve circular dependency between scroll offset and
   // compositing state, and remove this disabler.
   DisableCompositingQueryAsserts disabler;
 
   // Update the positions of our child layers (if needed as only fixed layers
   // should be impacted by a scroll).  We don't update compositing layers,
   // because we need to do a deep update from the compositing ancestor.
   if (!frameView->isInPerformLayout()) {
     // If we're in the middle of layout, we'll just update layers once layout
     // has finished.
-    layer()->updateLayerPositionsAfterOverflowScroll(scrollDelta);
+    layer()->updateLayerPositionsAfterOverflowScroll();
     // Update regions, scrolling may change the clip of a particular region.
     frameView->updateDocumentAnnotatedRegions();
     frameView->setNeedsUpdateWidgetGeometries();
     updateCompositingLayersAfterScroll();
   }
 
   const LayoutBoxModelObject& paintInvalidationContainer =
       box().containerForPaintInvalidation();
   // The caret rect needs to be invalidated after scrolling
   frame->selection().setCaretRectNeedsUpdate();
@@ skipping 1665 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     clampScrollableAreas() {
   for (auto& scrollableArea : *s_needsClamp)
     scrollableArea->clampScrollOffsetAfterOverflowChange();
   delete s_needsClamp;
   s_needsClamp = nullptr;
 }
 
 }  // namespace blink