Suppress layer creation for descendants of GPU-rasterized layers

Source/core/rendering/RenderLayerScrollableArea.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 370 matching lines @@
     else
         quadForFakeMouseMoveEvent = FloatQuad(layer()->repainter().repaintRect());
 
     if (repaintContainer)
         quadForFakeMouseMoveEvent = repaintContainer->localToAbsoluteQuad(quadForFakeMouseMoveEvent);
     frame->eventHandler().dispatchFakeMouseMoveEventSoonInQuad(quadForFakeMouseMoveEvent);
 
     bool requiresRepaint = true;
 
     if (m_box->view()->compositor()->inCompositingMode()) {
+        // Hits in virtual/gpu/fast/canvas/canvas-scroll-path-into-view.html.
+        DisableCompositingQueryAsserts disabler;
         bool onlyScrolledCompositedLayers = scrollsOverflow()
             && !layer()->hasVisibleNonLayerContent()
             && !layer()->hasNonCompositedChild()
             && !layer()->hasBlockSelectionGapBounds()
             && !m_box->isMarquee();
 
         if (usesCompositedScrolling() || onlyScrolledCompositedLayers)
             requiresRepaint = false;
     }
 
@@ skipping 1104 matching lines @@
 void RenderLayerScrollableArea::setForceNeedsCompositedScrolling(ForceNeedsCompositedScrollingMode mode)
 {
     if (m_forceNeedsCompositedScrolling == mode)
         return;
 
     m_forceNeedsCompositedScrolling = mode;
     layer()->didUpdateNeedsCompositedScrolling();
 }
 
 } // Namespace WebCore