Connect Login UI to SystemTray

ash/public/interfaces/system_tray.mojom

Index: ash/public/interfaces/system_tray.mojom
diff --git a/ash/public/interfaces/system_tray.mojom b/ash/public/interfaces/system_tray.mojom
index 7013d624fc09ddd191ff543b1fac028cabd0580c..14f9ea5cbd8cfed37f54bb79047b23a4e192d7bf 100644
--- a/ash/public/interfaces/system_tray.mojom
+++ b/ash/public/interfaces/system_tray.mojom
@@ -11,6 +11,13 @@ interface SystemTray {
   // Sets the client interface.
   SetClient(SystemTrayClient client);
 
+  // Sets the enabled state on the primary tray. If not |enabled| any open

[James Cook, 2017/01/09 19:30:05]

nit: on -> of. Also, I might say "tray on the primary display" here and below.

[jonross, 2017/01/09 22:01:35]

Done.

+  // menu will be closed.
+  SetPrimaryTrayEnabled(bool enabled);
+
+  // Sets the visibility of the primary tray.
+  SetPrimaryTrayVisible(bool visible);
+
   // Sets the clock to use 24 hour time formatting if |use_24_hour| is true.
   // Otherwise sets 12 hour time formatting.
   SetUse24HourClock(bool use_24_hour);