Disable some compositing state asserts seen on Mac builds

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 128 matching lines @@
         m_resizer->destroy();
 }
 
 GraphicsLayer* RenderLayerScrollableArea::layerForScrolling() const
 {
     return m_box->hasCompositedLayerMapping() ? m_box->compositedLayerMapping()->scrollingContentsLayer() : 0;
 }
 
 GraphicsLayer* RenderLayerScrollableArea::layerForHorizontalScrollbar() const
 {
+    // See crbug.com/343132.
+    DisableCompositingQueryAsserts disabler;
+
     return m_box->hasCompositedLayerMapping() ? m_box->compositedLayerMapping()->layerForHorizontalScrollbar() : 0;
 }
 
 GraphicsLayer* RenderLayerScrollableArea::layerForVerticalScrollbar() const
 {
+    // See crbug.com/343132.
+    DisableCompositingQueryAsserts disabler;
+
     return m_box->hasCompositedLayerMapping() ? m_box->compositedLayerMapping()->layerForVerticalScrollbar() : 0;
 }
 
 GraphicsLayer* RenderLayerScrollableArea::layerForScrollCorner() const
 {
+    // See crbug.com/343132.
+    DisableCompositingQueryAsserts disabler;
+
     return m_box->hasCompositedLayerMapping() ? m_box->compositedLayerMapping()->layerForScrollCorner() : 0;
 }
 
 void RenderLayerScrollableArea::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rect)
 {
+    // See crbug.com/343132.
+    DisableCompositingQueryAsserts disabler;
+
     if (scrollbar == m_vBar.get()) {
         if (GraphicsLayer* layer = layerForVerticalScrollbar()) {
             layer->setNeedsDisplayInRect(rect);
             return;
         }
     } else {
         if (GraphicsLayer* layer = layerForHorizontalScrollbar()) {
             layer->setNeedsDisplayInRect(rect);
             return;
         }
@@ skipping 1337 matching lines @@
 void RenderLayerScrollableArea::setForceNeedsCompositedScrolling(ForceNeedsCompositedScrollingMode mode)
 {
     if (m_forceNeedsCompositedScrolling == mode)
         return;
 
     m_forceNeedsCompositedScrolling = mode;
     layer()->didUpdateNeedsCompositedScrolling();
 }
 
 } // Namespace WebCore