Add an initial-setup mode

Use the newly introduced kiosk mode functionality, and define an
'initial-setup' mode that is suitable for
https://live.gnome.org/GnomeOS/Design/Whiteboards/InitialSetup

https://bugzilla.gnome.org/show_bug.cgi?id=676697

js/ui/main.js

@@ -99,6 +99,10 @@ function createGDMSession() {
                         });
 }
 
+function createInitialSetupSession() {
+    networkAgent = new NetworkAgent.NetworkAgent();
+}
+
 function _initRecorder() {
     let recorderSettings = new Gio.Settings({ schema: 'org.gnome.shell.recorder' });
     let bindingSettings = new Gio.Settings({ schema: 'org.gnome.shell.keybindings' });

js/ui/sessionMode.js

@@ -55,6 +55,28 @@ const _modes = {
              }
            },
 
+    'initial-setup': { hasOverview: false,
+                       hasAppMenu: false,
+                       showCalendarEvents: false,
+                       allowSettings: false,
+                       allowExtensions: false,
+                       allowKeybindingsWhenModal: false,
+                       hasRunDialog: false,
+                       hasWorkspaces: false,
+                       createSession: Main.createInitialSetupSession,
+                       extraStylesheet: null,
+                       statusArea: {
+                           order: [
+                               'a11y', 'keyboard', 'volume'
+                           ],
+                           implementation: {
+                               'a11y': imports.ui.status.accessibility.ATIndicator,
+                               'keyboard': imports.ui.status.keyboard.XKBIndicator,
+                               'volume': imports.ui.status.volume.Indicator
+                        }
+                }
+           },
+
     'user': { hasOverview: true,
               hasAppMenu: true,
               showCalendarEvents: true,