Add command line switches and about:flag to enable FPS indicator and compositor layer tree.

webkit/glue/webpreferences.h

Index: webkit/glue/webpreferences.h
diff --git a/webkit/glue/webpreferences.h b/webkit/glue/webpreferences.h
index 468e9b482a44bd5fd57fbd6bdee391dd464553f4..18535687eb2e1583dbbe47aa7e3c61735cc5e36e 100644
--- a/webkit/glue/webpreferences.h
+++ b/webkit/glue/webpreferences.h
@@ -70,6 +70,8 @@ struct WebPreferences {
   bool experimental_webgl_enabled;
   bool gl_multisampling_enabled;
   bool show_composited_layer_borders;
+  bool show_composited_layer_tree;
+  bool show_fps_counter;
   bool accelerated_compositing_enabled;
   bool accelerated_layers_enabled;
   bool accelerated_video_enabled;