webapp-container fails to inhibit screen blanking

[Olivier Tilloy]

When watching a video in the youtube webapp, the screen eventually blanks while the video is playing. I’m seeing this in the app’s log:

[0929/113347:ERROR:logging.h(739)] 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, 0 matched rules; type="method_call", sender=":1.110" (uid=32011 pid=11942 comm="webapp-container --webappUrlPatterns=https?://*.yo") interface="com.canonical.Unity.Screen" member="keepDisplayOn" error name="(unset)" requested_reply="0" destination="com.canonical.Unity.Screen" (uid=0 pid=2166 comm="unity-system-compositor --disable-overlays=false -")
[0929/113347:ERROR:oxide_power_save_blocker.cc(109)] Failed to inhibit screen blanking

Playing the same video in the webbrowser app does prevent the screen from blanking.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tom Haddon (mthaddon)]

Following syslog entry confirms:

Sep 29 11:02:50 ubuntu-phablet dbus[745]: apparmor="DENIED" operation="dbus_method_call" bus="system" path="/com/canonical/Unity/Screen" interface="com.canonical.Unity.Screen" member="keepDisplayOn" mask="send" name="com.canonical.Unity.Screen" pid=19918 profile="com.popey.youtube_youtube_0.3" peer_pid=1568 peer_profile="unconfined"

[Jamie Strandboge (jdstrand)]

This is because oxide doesn't yet use media-hub. Confined apps are not allowed to manipulate screen blanking because this breaks application lifecycle. FYI, I was specifically told not to allow this....