SF: Decouple MessageQueue

Define an ICompositor interface against which MessageQueue (which ought
to be an implementation detail of Scheduler) is implemented. Change the
equivocal invalidate/refresh nomenclature to commit/composite. Schedule
sampling only after composite.

Bug: 185535769
Test: libsurfaceflinger_unittest
Change-Id: I0c18f312459bae48531449f24f7b53c104fc5812
diff --git a/services/surfaceflinger/DisplayDevice.h b/services/surfaceflinger/DisplayDevice.h
index 4a731bd..4b9718f 100644
--- a/services/surfaceflinger/DisplayDevice.h
+++ b/services/surfaceflinger/DisplayDevice.h
@@ -234,7 +234,7 @@
     void enableRefreshRateOverlay(bool enable, bool showSpinner);
     bool isRefreshRateOverlayEnabled() const { return mRefreshRateOverlay != nullptr; }
     bool onKernelTimerChanged(std::optional<DisplayModeId>, bool timerExpired);
-    void onInvalidate();
+    void animateRefreshRateOverlay();
 
     void onVsync(nsecs_t timestamp);
     nsecs_t getVsyncPeriodFromHWC() const;