SF: Clean up RefreshRateOverlay

Flatten buffer cache, remove unused members, and fix conversion
warnings.

Skip animation transactions unless spinner is enabled.

Bug: 185535769
Bug: 129481165
Test: Apply follow-up fix and toggle overlay.
Change-Id: I14688f7b5d882f595322dfadd5cabbd5a8564301
diff --git a/services/surfaceflinger/DisplayDevice.cpp b/services/surfaceflinger/DisplayDevice.cpp
index f5a4b3d..9116fd3 100644
--- a/services/surfaceflinger/DisplayDevice.cpp
+++ b/services/surfaceflinger/DisplayDevice.cpp
@@ -471,9 +471,8 @@
         return;
     }
 
-    const auto [lowFps, highFps] = mRefreshRateConfigs->getSupportedRefreshRateRange();
-    mRefreshRateOverlay = std::make_unique<RefreshRateOverlay>(*mFlinger, lowFps.getIntValue(),
-                                                               highFps.getIntValue(), showSpinnner);
+    const auto fpsRange = mRefreshRateConfigs->getSupportedRefreshRateRange();
+    mRefreshRateOverlay = std::make_unique<RefreshRateOverlay>(fpsRange, showSpinnner);
     mRefreshRateOverlay->setLayerStack(getLayerStack());
     mRefreshRateOverlay->setViewport(getSize());
     mRefreshRateOverlay->changeRefreshRate(getActiveMode()->getFps());