cc: Allow sending BeginMainFrame before draw or activation

cc/trees/layer_tree_settings.h

Index: cc/trees/layer_tree_settings.h
diff --git a/cc/trees/layer_tree_settings.h b/cc/trees/layer_tree_settings.h
index 0e15ef1c7d60519b54c4baaf57dc84a2fbce6510..f2f591e1523561b9652bba0bdc255368ed2eb579 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -25,6 +25,8 @@ class CC_EXPORT LayerTreeSettings {
   bool throttle_frame_production;
   bool begin_frame_scheduling_enabled;
   bool deadline_scheduling_enabled;
+  bool start_commit_before_draw_enabled;
+  bool start_commit_before_activate_enabled;
   bool using_synchronous_renderer_compositor;
   bool per_tile_painting_enabled;
   bool partial_swap_enabled;