[SurfaceFlinger] Split VSyncModulator into .cpp/.h files

Future changes require this so that trace events can be added for this
class.

Bug: 133325345
Test: builds
Change-Id: I7b70a9df500b0fca5ae14e2b414d44ca11edf3ce
diff --git a/services/surfaceflinger/Android.bp b/services/surfaceflinger/Android.bp
index 4cd0a13..501d176 100644
--- a/services/surfaceflinger/Android.bp
+++ b/services/surfaceflinger/Android.bp
@@ -149,9 +149,10 @@
         "Scheduler/LayerHistory.cpp",
         "Scheduler/LayerInfo.cpp",
         "Scheduler/MessageQueue.cpp",
+        "Scheduler/PhaseOffsets.cpp",
         "Scheduler/Scheduler.cpp",
         "Scheduler/SchedulerUtils.cpp",
-        "Scheduler/PhaseOffsets.cpp",
+        "Scheduler/VSyncModulator.cpp",
         "StartPropertySetThread.cpp",
         "SurfaceFlinger.cpp",
         "SurfaceInterceptor.cpp",