CC: Plumb LayerSettings parameter for cc::Layer construction.

content/public/test/layouttest_support.h

Index: content/public/test/layouttest_support.h
diff --git a/content/public/test/layouttest_support.h b/content/public/test/layouttest_support.h
index c8ec1e5d86ad69a13fd41fd1f31464e150e2afd1..413842c769cdf80acae2339649c3ca5a9e46811d 100644
--- a/content/public/test/layouttest_support.h
+++ b/content/public/test/layouttest_support.h
@@ -125,6 +125,10 @@ void DisableAutoResizeMode(RenderView* render_view,
 std::string DumpBackForwardList(std::vector<PageState>& page_state,
                                 size_t current_index);
 
+// Creates cc::TextureLayer for TestPlugin.
+scoped_refptr<cc::TextureLayer> CreateTextureLayerForMailbox(
+    cc::TextureLayerClient* client);
+
 // Instantiates WebLayerImpl for TestPlugin.
 blink::WebLayer* InstantiateWebLayer(scoped_refptr<cc::TextureLayer> layer);