LoginManager: Add canRebootToBootLoaderMenu and setRebootToBootLoaderMenu methods

Add wrappers for the new logind Manager CanRebootToBootLoaderMenu and
SetRebootToBootLoaderMenu dbus methods.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/199

data/dbus-interfaces/org.freedesktop.login1.Manager.xml

@@ -20,6 +20,12 @@
     <method name="ListSessions">
       <arg name="sessions" type="a(susso)" direction="out"/>
     </method>
+    <method name="CanRebootToBootLoaderMenu">
+      <arg type="s" direction="out"/>
+    </method>
+    <method name="SetRebootToBootLoaderMenu">
+      <arg type="t" direction="in"/>
+    </method>
     <signal name="PrepareForSleep">
       <arg type="b" direction="out"/>
     </signal>

js/misc/loginManager.js

@@ -158,6 +158,23 @@ var LoginManagerSystemd = class {
         });
     }
 
+    canRebootToBootLoaderMenu(asyncCallback) {
+        this._proxy.CanRebootToBootLoaderMenuRemote((result, error) => {
+            if (error) {
+                asyncCallback(false, false);
+            } else {
+                const needsAuth = result[0] === 'challenge';
+                const canRebootToBootLoaderMenu = needsAuth || result[0] === 'yes';
+                asyncCallback(canRebootToBootLoaderMenu, needsAuth);
+            }
+        });
+    }
+
+    setRebootToBootLoaderMenu() {
+        /* Parameter is timeout in usec, show to menu for 60 seconds */
+        this._proxy.SetRebootToBootLoaderMenuRemote(60000000);
+    }
+
     listSessions(asyncCallback) {
         this._proxy.ListSessionsRemote((result, error) => {
             if (error)
@@ -203,6 +220,13 @@ var LoginManagerDummy = class {
         asyncCallback(false, false);
     }
 
+    canRebootToBootLoaderMenu(asyncCallback) {
+        asyncCallback(false, false);
+    }
+
+    setRebootToBootLoaderMenu() {
+    }
+
     listSessions(asyncCallback) {
         asyncCallback([]);
     }