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 6c06254e0b2a2f7804b2218fbf579a2ea782ba48..0591594ff74b3fea5fa250ab538c7b4c897d6d3e 100644
--- a/cc/trees/layer_tree_settings.h
+++ b/cc/trees/layer_tree_settings.h
@@ -23,6 +23,8 @@ class CC_EXPORT LayerTreeSettings {
   bool throttle_frame_production;
   bool begin_impl_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;