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/Scheduler/Scheduler.h b/services/surfaceflinger/Scheduler/Scheduler.h
index 9c32b1f..f6c81c0 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.h
+++ b/services/surfaceflinger/Scheduler/Scheduler.h
@@ -169,6 +169,7 @@
     // The period is the vsync period from the current display configuration.
     void resyncToHardwareVsync(bool makeAvailable, nsecs_t period);
     void resync() EXCLUDES(mRefreshRateConfigsLock);
+    void forceNextResync() { mLastResyncTime = 0; }
 
     // Passes a vsync sample to VsyncController. periodFlushed will be true if
     // VsyncController detected that the vsync period changed, and false otherwise.