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/tests/unittests/FpsOps.h b/services/surfaceflinger/tests/unittests/FpsOps.h
index 23c2841..7c737dc 100644
--- a/services/surfaceflinger/tests/unittests/FpsOps.h
+++ b/services/surfaceflinger/tests/unittests/FpsOps.h
@@ -16,7 +16,7 @@
 
 #pragma once
 
-#include "Fps.h"
+#include <scheduler/Fps.h>
 
 namespace android {