Adds getSupportedRefreshRates support

Source values for refresh rates from the RefreshRateSelector
through SurfaceComposerClient.

Test: atest android.display.cts.DisplayTest
BUG: 365163968
Flag: com.android.server.display.feature.flags.enable_get_supported_refresh_rates
Change-Id: I149e6e51b3b3718ef53e522f1fca5650dbbd8b7b
diff --git a/services/surfaceflinger/Scheduler/RefreshRateSelector.h b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
index ee3a4f7..508f9d7 100644
--- a/services/surfaceflinger/Scheduler/RefreshRateSelector.h
+++ b/services/surfaceflinger/Scheduler/RefreshRateSelector.h
@@ -441,6 +441,8 @@
 
     std::pair<Fps, Fps> getFrameRateCategoryRates() const { return kFrameRateCategoryRates; }
 
+    std::vector<float> getSupportedFrameRates() const EXCLUDES(mLock);
+
 private:
     friend struct TestableRefreshRateSelector;