cc: Add trace events to track main thread latency mode

cc/scheduler/scheduler_state_machine.cc

Index: cc/scheduler/scheduler_state_machine.cc
diff --git a/cc/scheduler/scheduler_state_machine.cc b/cc/scheduler/scheduler_state_machine.cc
index 8f38a33d7e31f7299dac0afa87a939b61ce86b8b..bd0500ebe5b014126347167eedd1eb0791d4e760 100644
--- a/cc/scheduler/scheduler_state_machine.cc
+++ b/cc/scheduler/scheduler_state_machine.cc
@@ -703,6 +703,9 @@ void SchedulerStateMachine::UpdateStateOnManageTiles() {
 }
 
 void SchedulerStateMachine::SetSkipNextBeginMainFrameToReduceLatency() {
+  TRACE_EVENT_INSTANT0("cc",
+                       "Scheduler: SkipNextBeginMainFrameToReduceLatency",
+                       TRACE_EVENT_SCOPE_THREAD);
   skip_next_begin_main_frame_to_reduce_latency_ = true;
 }