SurfaceFlinger: DispSync -> VsyncController

Refactor the old DispSync to separate between Vsync math (VsyncTracker)
and fence / vsync callback management (VsyncController)

Bug: 162888874
Test: examine systraces
Test: SF unit tests

Change-Id: Id275620380a21aeb0017e966910cbf24860cecef
diff --git a/libs/gui/include/gui/DisplayEventReceiver.h b/libs/gui/include/gui/DisplayEventReceiver.h
index 7974a06..0d0d102 100644
--- a/libs/gui/include/gui/DisplayEventReceiver.h
+++ b/libs/gui/include/gui/DisplayEventReceiver.h
@@ -72,6 +72,7 @@
         struct VSync {
             uint32_t count;
             nsecs_t expectedVSyncTimestamp __attribute__((aligned(8)));
+            nsecs_t deadlineTimestamp __attribute__((aligned(8)));
         };
 
         struct Hotplug {