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

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 7baf7edc03eaaca5837c346f513afc3b1025e21a..fa5b5a1ef9a539599056f3adfb82d8111ab9da79 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -5629,8 +5629,9 @@ void RenderLayer::rebuildZOrderLists(OwnPtr<Vector<RenderLayer*> >& posZOrderLis
         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());
             }
         }
     }