cc: Allow sending BeginMainFrame before draw or activation

cc/scheduler/scheduler_settings.h

Index: cc/scheduler/scheduler_settings.h
diff --git a/cc/scheduler/scheduler_settings.h b/cc/scheduler/scheduler_settings.h
index 251328ed6772ecb1a35183d588cbeb1952d97b98..78a72441bee0be14151cfd3e2980b25d9308741d 100644
--- a/cc/scheduler/scheduler_settings.h
+++ b/cc/scheduler/scheduler_settings.h
@@ -14,6 +14,8 @@ class CC_EXPORT SchedulerSettings {
   SchedulerSettings();
   ~SchedulerSettings();
 
+  bool start_commit_before_draw_enabled;
+  bool start_commit_before_activate_enabled;
   bool impl_side_painting;
   bool timeout_and_draw_when_animation_checkerboards;
   int maximum_number_of_failed_draws_before_draw_is_forced_;