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/Scheduler/VSyncTracker.h b/services/surfaceflinger/Scheduler/VSyncTracker.h
index 95750ad..76315d2 100644
--- a/services/surfaceflinger/Scheduler/VSyncTracker.h
+++ b/services/surfaceflinger/Scheduler/VSyncTracker.h
@@ -17,7 +17,9 @@
 #pragma once
 
 #include <utils/Timers.h>
-#include "Fps.h"
+
+#include <scheduler/Fps.h>
+
 #include "VSyncDispatch.h"
 
 namespace android::scheduler {