SF: move RefreshRateOverlay to DisplayDevice

Test: SF unit tests
Test: refresh rate overlay is visible on all displays
Bug: 187539899
Change-Id: I3bfa3749dcd5bbd7d6238a60332b98bba954ca53
diff --git a/services/surfaceflinger/RefreshRateOverlay.h b/services/surfaceflinger/RefreshRateOverlay.h
index aa8329c..f9baa89 100644
--- a/services/surfaceflinger/RefreshRateOverlay.h
+++ b/services/surfaceflinger/RefreshRateOverlay.h
@@ -37,12 +37,12 @@
 
 class RefreshRateOverlay {
 public:
-    RefreshRateOverlay(SurfaceFlinger&, bool showSpinner);
+    RefreshRateOverlay(SurfaceFlinger&, uint32_t lowFps, uint32_t highFps, bool showSpinner);
 
+    void setLayerStack(uint32_t stack);
     void setViewport(ui::Size);
     void changeRefreshRate(const Fps&);
     void onInvalidate();
-    void reset();
 
 private:
     class SevenSegmentDrawer {
@@ -91,8 +91,8 @@
     const bool mShowSpinner;
 
     // Interpolate the colors between these values.
-    uint32_t mLowFps;
-    uint32_t mHighFps;
+    const uint32_t mLowFps;
+    const uint32_t mHighFps;
 };
 
 } // namespace android