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 8bb8a9d565875f8e53dc4b7fba6042c7f01eb7db..e8e34cd9ba42d6f40ad437cc0f88737049a34961 100644
--- a/cc/test/scheduler_test_common.h
+++ b/cc/test/scheduler_test_common.h
@@ -129,11 +129,6 @@ class TestScheduler : public Scheduler {
       BeginFrameSource* begin_frame_source,
       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 {
@@ -150,6 +145,10 @@ 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() {