SF: add HWVsync state to dumpsys

Log debugging information about whether HWVsync callbacks
where enabled with HWC.

Bug: 201605862
Test: adb logcat -s SurfaceFlinger
Change-Id: Iaa13a92d37fcfea1328a6e91b17372c3737ffff6
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index dba2bd6..9e2e216 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -1064,6 +1064,11 @@
      */
     nsecs_t getVsyncPeriodFromHWC() const REQUIRES(mStateLock);
 
+    void setHWCVsyncEnabled(PhysicalDisplayId id, hal::Vsync enabled) {
+        mLastHWCVsyncState = enabled;
+        getHwComposer().setVsyncEnabled(id, enabled);
+    }
+
     // Sets the refresh rate by switching active configs, if they are available for
     // the desired refresh rate.
     void changeRefreshRateLocked(const RefreshRate&, Scheduler::ModeEvent) REQUIRES(mStateLock);
@@ -1422,6 +1427,7 @@
     std::atomic<nsecs_t> mExpectedPresentTime = 0;
     nsecs_t mScheduledPresentTime = 0;
     hal::Vsync mHWCVsyncPendingState = hal::Vsync::DISABLE;
+    hal::Vsync mLastHWCVsyncState = hal::Vsync::DISABLE;
 
     // below flags are set by main thread only
     bool mSetActiveModePending = false;