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 0a48b474988bf81767fae11b2b33eedc9f5f632f..4de7110e73cc68af8008f455c70279994253ccc4 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -22,6 +22,8 @@ class CC_EXPORT LayerTreeSettings {
   bool allow_antialiasing;
   bool throttle_frame_production;
   bool begin_impl_frame_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;