Use transitions for shade window occluded state

There is a timing issue that shows up with activity
launch animations. If keyguard occluded state is
changed in the middle of a launch animation, a flicker
can occur, sometimes pretty bad like currently
lauching the emergency call UI over SIM bouncer. Use
transition FINISHED state as a more reliable method
to send state over to the shade window.

Fixes: 344716537
Test: atest NotificationShadeWindowModelTest
Test: manual repeatedly launch emergency call UI
over SIM bouncer
Flag: com.android.systemui.use_transitions_for_keyguard_occluded

Change-Id: I14e1c3478fb76c3a9459c3a8fd0d8e4587962089
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 1f1495a..0d337eb 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -1263,6 +1263,16 @@
 }
 
 flag {
+   name: "use_transitions_for_keyguard_occluded"
+   namespace: "systemui"
+   description: "Use Keyguard Transitions to set Notification Shade occlusion state"
+   bug: "344716537"
+   metadata {
+        purpose: PURPOSE_BUGFIX
+   }
+}
+
+flag {
    name: "lockscreen_preview_renderer_create_on_main_thread"
    namespace: "systemui"
    description: "Force preview renderer to be created on the main thread"