SF: set active config state machine

1) Set the desired active config bit
2) On the next vsync, ask HWC to update config.
3) Send a refresh to HWC
4) When the fence comes back, update SF to the new config/refresh rate
   and trigger HWC vsync.

see go/surface-flinger-scheduler for more info

Test: Systrace.
Change-Id: I4ed649668cc6cc23cd3f428b3c92ab1c199c8aa4
diff --git a/services/surfaceflinger/Scheduler/Scheduler.cpp b/services/surfaceflinger/Scheduler/Scheduler.cpp
index 2f581d2..cb83c62 100644
--- a/services/surfaceflinger/Scheduler/Scheduler.cpp
+++ b/services/surfaceflinger/Scheduler/Scheduler.cpp
@@ -69,7 +69,7 @@
     mEventControlThread = std::make_unique<impl::EventControlThread>(function);
 
     char value[PROPERTY_VALUE_MAX];
-    property_get("debug.sf.set_idle_timer_ms", value, "30");
+    property_get("debug.sf.set_idle_timer_ms", value, "0");
     mSetIdleTimerMs = atoi(value);
 
     if (mSetIdleTimerMs > 0) {