SF: handle onComposerHalVsyncIdle

Tell Scheduler to force resync on the next resync request
when onComposerHalVsyncIdle callback is called.

Bug: 198106220
Test: manually calling onComposerHalVsyncIdle from backdoor
Change-Id: I6875c0ba44ef4de2c025491830fbb0bb710093bd
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index ab45b4c..7cf276e 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -1957,8 +1957,8 @@
 }
 
 void SurfaceFlinger::onComposerHalVsyncIdle(hal::HWDisplayId) {
-    // TODO(b/198106220): force enable HWVsync to avoid drift problem during
-    // idle.
+    ATRACE_CALL();
+    mScheduler->forceNextResync();
 }
 
 void SurfaceFlinger::setVsyncEnabled(bool enabled) {