Refactor repainting logic to abstract away the specific repaint container.

Source/core/rendering/compositing/RenderLayerCompositor.cpp

Index: Source/core/rendering/compositing/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/compositing/RenderLayerCompositor.cpp b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
index 435b95f03c62af86d2da469ecb0fba47739a31ba..3e9cba133ac3fb10639de02117c7e14eeaee11f1 100644
--- a/Source/core/rendering/compositing/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/compositing/RenderLayerCompositor.cpp
@@ -622,9 +622,7 @@ void RenderLayerCompositor::repaintOnCompositingChange(RenderLayer* layer)
     if (layer->renderer() != &m_renderView && !layer->renderer()->parent())
         return;
 
-    const RenderLayerModelObject* repaintContainer = layer->renderer()->containerForRepaint();
-    ASSERT(repaintContainer);
-    layer->repainter().repaintIncludingNonCompositingDescendants(repaintContainer);
+    layer->repainter().repaintIncludingNonCompositingDescendants();
 }
 
 // This method assumes that layout is up-to-date, unlike repaintOnCompositingChange().