Merge "Avoid initialization race condition"

packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java

@@ -561,7 +561,7 @@ public class ScrimController implements ViewTreeObserver.OnPreDrawListener, OnCo
     }
 
     protected void scheduleUpdate() {
-        if (mUpdatePending) return;
+        if (mUpdatePending || mScrimBehind == null) return;
 
         // Make sure that a frame gets scheduled.
         mScrimBehind.invalidate();