QS Guest fixes

- Fixes NPE when guest has not been created yet
- Reloads pictures only when they changed
- Adds "Exit guest" affordance

Bug: 16363920
Bug: 15759638
Change-Id: I99ff1c4be06fee96c5169fd7c2d31b1b13f7a389
diff --git a/packages/SystemUI/AndroidManifest.xml b/packages/SystemUI/AndroidManifest.xml
index b7210e1..5752646 100644
--- a/packages/SystemUI/AndroidManifest.xml
+++ b/packages/SystemUI/AndroidManifest.xml
@@ -70,6 +70,7 @@
     <uses-permission android:name="android.permission.STOP_APP_SWITCHES" />
     <uses-permission android:name="android.permission.SET_SCREEN_COMPATIBILITY" />
     <uses-permission android:name="android.permission.START_ANY_ACTIVITY" />
+    <uses-permission android:name="android.permission.INTERACT_ACROSS_USERS" />
     <uses-permission android:name="android.permission.INTERACT_ACROSS_USERS_FULL" />
     <uses-permission android:name="android.permission.GET_TOP_ACTIVITY_INFO" />
     <uses-permission android:name="android.permission.MANAGE_ACTIVITY_STACKS" />