Reland of cc: Remove frame queuing from the scheduler.

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 c3d6753bb228f1c4eccdfdd4e8e0b73a25233f7a..b13341bcce37ea8546d1431f1ff6a6e05a88ece3 100644
--- a/cc/test/scheduler_test_common.h
+++ b/cc/test/scheduler_test_common.h
@@ -128,11 +128,6 @@ class TestScheduler : public Scheduler {
       OrderedSimpleTaskRunner* task_runner,
       std::unique_ptr<CompositorTimingHistory> compositor_timing_history);
 
-  // Extra test helper functionality
-  bool IsBeginRetroFrameArgsEmpty() const {
-    return begin_retro_frame_args_.empty();
-  }
-
   bool SwapThrottled() const { return state_machine_.SwapThrottled(); }
 
   bool NeedsBeginMainFrame() const {
@@ -149,6 +144,10 @@ class TestScheduler : public Scheduler {
     return begin_frame_source_ && observing_begin_frame_source_;
   }
 
+  int current_frame_number() const {
+    return state_machine_.current_frame_number();
+  }
+
   ~TestScheduler() override;
 
   base::TimeDelta BeginImplFrameInterval() {