Fix ASSERT failure in RenderGeometryMap.

Source/core/rendering/RenderLayer.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 640 matching lines @@
 
 void RenderLayer::updateLayerPositionsAfterScroll(RenderGeometryMap* geometryMap, UpdateLayerPositionsAfterScrollFlags flags)
 {
     // FIXME: This shouldn't be needed, but there are some corner cases where
     // these flags are still dirty. Update so that the check below is valid.
     updateDescendantDependentFlags();
 
     // If we have no visible content and no visible descendants, there is no point recomputing
     // our rectangles as they will be empty. If our visibility changes, we are expected to
     // recompute all our positions anyway.
-    if (!m_hasVisibleDescendant && !m_hasVisibleContent)
+    if (subtreeIsInvisible())
         return;
 
     bool positionChanged = updateLayerPosition();
     if (positionChanged)
         flags |= HasChangedAncestor;
 
     if (geometryMap)
         geometryMap->pushMappingsToAncestor(this, parent());
 
     if (flags & HasChangedAncestor || flags & HasSeenViewportConstrainedAncestor || flags & IsOverflowScroll)
@@ skipping 4564 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif