keepDisplayOn denied by apparmor

[Sebastien Bacher]

Using ota8 (or current rc-proposed), if you click on a youtube video in the facebook webapp you get those warnings

"[1202/145449:ERROR:logging.h(810)] Failed to call method: com.canonical.Unity.Screen.keepDisplayOn: object_path= /com/canonical/Unity/Screen: org.freedesktop.DBus.Error.AccessDenied: An AppArmor policy prevents this sender from sending this message to this recipient; type="method_call", sender=":1.142" (uid=32011 pid=5112 comm="webapp-container --enable-back-forward --accountPr") interface="com.canonical.Unity.Screen" member="keepDisplayOn" error name="(unset)" requested_reply="0" destination="com.canonical.Unity.Screen" (uid=0 pid=1636 comm="unity-system-compositor --disable-overlays=false -")"

The profile for the facebook app should probably include keepdisplayon