Delay scrollContents until the next paint

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 2bf77db422f5707a56f4a906df7b2dda6eaa3d09..4bd5f3e1d2fea151233bd9008fbaa1b233040a21 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -487,7 +487,7 @@ void RenderLayer::updateLayerPositionsAfterScroll(RenderGeometryMap* geometryMap
     if (geometryMap)
         geometryMap->pushMappingsToAncestor(this, parent());
 
-    if (flags & HasChangedAncestor || flags & HasSeenViewportConstrainedAncestor || flags & IsOverflowScroll)
+    if ((flags & HasChangedAncestor) || (flags & HasSeenViewportConstrainedAncestor) || (flags & IsOverflowScroll))
         m_clipper.clearClipRects();
 
     if (renderer()->style()->hasViewportConstrainedPosition())
@@ -496,11 +496,7 @@ void RenderLayer::updateLayerPositionsAfterScroll(RenderGeometryMap* geometryMap
     if (renderer()->hasOverflowClip())
         flags |= HasSeenAncestorWithOverflowClip;
 
-    if (flags & HasSeenViewportConstrainedAncestor
-        || (flags & IsOverflowScroll && flags & HasSeenAncestorWithOverflowClip && !m_canSkipRepaintRectsUpdateOnScroll)) {
-        // FIXME: Remove incremental compositing updates after fixing the chicken/egg issues
-        // https://code.google.com/p/chromium/issues/detail?id=343756
-        DisableCompositingQueryAsserts disabler;
+    if ((flags & IsOverflowScroll) && (flags & HasSeenAncestorWithOverflowClip) && !m_canSkipRepaintRectsUpdateOnScroll) {
         // FIXME: We could track the repaint container as we walk down the tree.
         repainter().computeRepaintRects(renderer()->containerForRepaint(), geometryMap);
     } else {