SF: Set up libscheduler headers

Start pulling Scheduler sources into a libscheduler target akin to
librenderengine and libcompositionengine.

Bug: 185535769
Test: Build
Change-Id: I8ee871cce96209c8c53601152501129b09c5e46f
diff --git a/services/surfaceflinger/RefreshRateOverlay.cpp b/services/surfaceflinger/RefreshRateOverlay.cpp
index 2502d66..712ab16 100644
--- a/services/surfaceflinger/RefreshRateOverlay.cpp
+++ b/services/surfaceflinger/RefreshRateOverlay.cpp
@@ -276,7 +276,7 @@
     t.apply();
 }
 
-void RefreshRateOverlay::changeRefreshRate(const Fps& fps) {
+void RefreshRateOverlay::changeRefreshRate(Fps fps) {
     mCurrentFps = fps.getIntValue();
     auto buffer = getOrCreateBuffers(*mCurrentFps)[mFrame];
     SurfaceComposerClient::Transaction t;