needsFixedRootBackgroundLayer  443 Source/core/rendering/compositing/CompositedLayerMapping.cpp     setBackgroundLayerPaintsFixedRootBackground(compositor->needsFixedRootBackgroundLayer(&m_owningLayer));
needsFixedRootBackgroundLayer  124 Source/core/rendering/compositing/RenderLayerCompositor.h     bool needsFixedRootBackgroundLayer(const RenderLayer*) const;