cc: Simplify and rename MainThreadIsInHighLatency logic

cc/test/scheduler_test_common.h

Index: cc/test/scheduler_test_common.h
diff --git a/cc/test/scheduler_test_common.h b/cc/test/scheduler_test_common.h
index ef45ae9939ff5401f87e23deed135ce248f02e97..79770f4d97ef9e8e69b8305bce78413ebc95aadd 100644
--- a/cc/test/scheduler_test_common.h
+++ b/cc/test/scheduler_test_common.h
@@ -222,8 +222,8 @@ class TestScheduler : public Scheduler {
   BeginFrameSource& frame_source() { return *frame_source_; }
   bool FrameProductionThrottled() { return throttle_frame_production_; }
 
-  bool MainThreadIsInHighLatencyMode() const {
-    return state_machine_.MainThreadIsInHighLatencyMode();
+  bool MainThreadMissedLastDeadline() const {
+    return state_machine_.main_thread_missed_last_deadline();
   }
 
   ~TestScheduler() override;