Revert of Move some scroll invalidations to the paint invalidation phase

Source/core/rendering/RenderLayerRepainter.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@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 73 matching lines @@
 
     // Disable for reading compositingState() below.
     DisableCompositingQueryAsserts disabler;
 
     for (RenderLayer* curr = m_renderer.layer()->firstChild(); curr; curr = curr->nextSibling()) {
         if (curr->compositingState() != PaintsIntoOwnBacking && curr->compositingState() != PaintsIntoGroupedBacking)
             curr->paintInvalidator().paintInvalidationIncludingNonCompositingDescendantsInternal(paintInvalidationContainer);
     }
 }
 
+LayoutRect RenderLayerRepainter::paintInvalidationRectIncludingNonCompositingDescendants() const
+{
+    LayoutRect paintInvalidationRect = m_renderer.previousPaintInvalidationRect();
+
+    for (RenderLayer* child = m_renderer.layer()->firstChild(); child; child = child->nextSibling()) {
+        // Don't include paint invalidation rects for composited child layers; they will paint themselves and have a different origin.
+        if (child->compositingState() == PaintsIntoOwnBacking || child->compositingState() == PaintsIntoGroupedBacking)
+            continue;
+
+        paintInvalidationRect.unite(child->paintInvalidator().paintInvalidationRectIncludingNonCompositingDescendants());
+    }
+    return paintInvalidationRect;
+}
+
 void RenderLayerRepainter::setBackingNeedsPaintInvalidationInRect(const LayoutRect& r)
 {
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,
     // so assert but check that the layer is composited.
     ASSERT(m_renderer.compositingState() != NotComposited);
     // FIXME: generalize accessors to backing GraphicsLayers so that this code is squashing-agnostic.
     if (m_renderer.layer()->groupedMapping()) {
         LayoutRect paintInvalidationRect = r;
         paintInvalidationRect.move(m_renderer.layer()->subpixelAccumulation());
         if (GraphicsLayer* squashingLayer = m_renderer.layer()->groupedMapping()->squashingLayer())
@@ skipping 41 matching lines @@
 RenderLayer* RenderLayerRepainter::enclosingFilterPaintInvalidationLayer() const
 {
     for (const RenderLayer* curr = m_renderer.layer(); curr; curr = curr->parent()) {
         if ((curr != m_renderer.layer() && curr->requiresFullLayerImageForFilters()) || curr->compositingState() == PaintsIntoOwnBacking || curr->isRootLayer())
             return const_cast<RenderLayer*>(curr);
     }
     return 0;
 }
 
 } // namespace blink