[WIP] Migrate Fullscreen to use top layer instead of RenderFullScreen

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 5611 matching lines @@
     if (negZOrderList)
         std::stable_sort(negZOrderList->begin(), negZOrderList->end(), compareZIndex);
 
     // Append layers for top layer elements after normal layer collection, to ensure they are on top regardless of z-indexes.
     // The renderers of top layer elements are children of the view, sorted in top layer stacking order.
     if (isRootLayer()) {
         RenderObject* view = renderer()->view();
         for (RenderObject* child = view->firstChild(); child; child = child->nextSibling()) {
             Element* childElement = (child->node() && child->node()->isElementNode()) ? toElement(child->node()) : 0;
             if (childElement && childElement->isInTopLayer()) {
-                RenderLayer* layer = toRenderLayerModelObject(child)->layer();
-                posZOrderList->append(layer);
+                if (!posZOrderList)
+                    posZOrderList = adoptPtr(new Vector<RenderLayer*>);
+                posZOrderList->append(toRenderLayerModelObject(child)->layer());
             }
         }
     }
 }
 
 void RenderLayer::updateNormalFlowList()
 {
     if (!m_normalFlowListDirty)
         return;
 
@@ skipping 749 matching lines @@
     }
 }
 
 void showLayerTree(const WebCore::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif