messageTray: Add NotificationBanner actor

We no longer have a single notification actor that is either displayed
as banner or reparented to the summary depending on state - both the
lock screen and the notification section of the message list create
their own UI based on the information attached to the notification
object. Adding to this that different representations of a notification
may now exist simultaneously (as they are included in the message list
immediately rather than after the banner has been displayed), it no
longer makes sense to keep the banner actor in the notification itself.

Add a new NotificationBanner class that provides a separate banner
implementation based on the message list's NotificationMessage that will
soon replace the existing notification banners.

data/theme/gnome-shell-sass

@@ -1 +1 @@
-Subproject commit 860102c31bda598df340f2d68ea5be18e52da176
+Subproject commit de2baea3f921a28160a9be154683776338c1b5c2

data/theme/gnome-shell.css

@@ -1146,6 +1146,39 @@ StScrollBar {
 .url-highlighter {
   link-color: #215d9c; }
 
+.notification-banner {
+  font-size: 11pt;
+  width: 34em;
+  margin: 5px;
+  border-radius: 6px;
+  color: #eeeeec;
+  background-color: #2e3436;
+  border: 1px solid #1c1f1f; }
+  .notification-banner:hover {
+    background-color: #2e3436; }
+  .notification-banner:focus {
+    background-color: #2e3436; }
+  .notification-banner .notification-icon {
+    padding: 5px; }
+  .notification-banner .notification-content {
+    padding: 5px;
+    spacing: 5px; }
+  .notification-banner .secondary-icon {
+    icon-size: 1.09em; }
+  .notification-banner .notification-actions {
+    background-color: #1c1f1f;
+    padding-top: 2px;
+    spacing: 1px; }
+  .notification-banner .notification-button {
+    padding: 4px 4px 5px;
+    background-color: #222728; }
+    .notification-banner .notification-button:first-child {
+      border-radius: 0 0 0 6px; }
+    .notification-banner .notification-button:last-child {
+      border-radius: 0 0 6px 0; }
+    .notification-banner .notification-button:hover, .notification-banner .notification-buttonfocus {
+      background-color: #292f30; }
+
 .notification {
   font-size: 11pt;
   width: 34em;

js/ui/messageTray.js

@@ -13,6 +13,7 @@ const Shell = imports.gi.Shell;
 const Signals = imports.signals;
 const St = imports.gi.St;
 
+const Calendar = imports.ui.calendar;
 const GnomeSession = imports.misc.gnomeSession;
 const Main = imports.ui.main;
 const Params = imports.misc.params;
@@ -1105,6 +1106,97 @@ const Notification = new Lang.Class({
 });
 Signals.addSignalMethods(Notification.prototype);
 
+const NotificationBanner = new Lang.Class({
+    Name: 'NotificationBanner',
+    Extends: Calendar.NotificationMessage,
+
+    _init: function(notification) {
+        this.parent(notification);
+
+        this.actor.add_style_class_name('notification-banner');
+        this.actor.connect('destroy', Lang.bind(this, this._onDestroyed));
+
+        this._buttonBox = null;
+
+        this._addActions();
+        this._addSecondaryIcon();
+
+        this._activatedId = this.notification.connect('activated',
+            Lang.bind(this, function() {
+                // We hide all types of notifications once the user clicks on
+                // them because the common outcome of clicking should be the
+                // relevant window being brought forward and the user's
+                // attention switching to the window.
+                this.emit('done-displaying');
+            }));
+    },
+
+    _onDestroyed: function() {
+        this.notification.disconnect(this._activatedId);
+    },
+
+    _onUpdated: function(n, clear) {
+        this.parent(n, clear);
+
+        if (clear) {
+            this.setSecondaryActor(null);
+            this.setActionArea(null);
+            this._buttonBox = null;
+        }
+
+        this._addActions();
+        this._addSecondaryIcon();
+    },
+
+    _addActions: function() {
+        this.notification.actions.forEach(Lang.bind(this,
+            function(action) {
+                this.addAction(action.label, action.callback);
+            }));
+    },
+
+    _addSecondaryIcon: function() {
+        if (this.notification.secondaryGIcon) {
+            let icon = new St.Icon({ gicon: this.notification.secondaryGIcon });
+            this.setSecondaryActor(icon);
+        }
+    },
+
+    addButton: function(button, callback) {
+        if (!this._buttonBox) {
+            this._buttonBox = new St.BoxLayout({ style_class: 'notification-actions',
+                                                 x_expand: true });
+            this.setActionArea(this._buttonBox);
+            global.focus_manager.add_group(this._buttonBox);
+        }
+
+        this._buttonBox.add(button);
+        button.connect('clicked', Lang.bind(this, function() {
+            callback();
+
+            if (!this.notification.resident) {
+                // We don't hide a resident notification when the user invokes one of its actions,
+                // because it is common for such notifications to update themselves with new
+                // information based on the action. We'd like to display the updated information
+                // in place, rather than pop-up a new notification.
+                this.emit('done-displaying');
+                this.notification.destroy();
+            }
+        }));
+
+        return button;
+    },
+
+    addAction: function(label, callback) {
+        let button = new St.Button({ style_class: 'notification-button',
+                                     label: label,
+                                     x_expand: true,
+                                     can_focus: true });
+
+        return this.addButton(button, callback);
+    }
+});
+
 const SourceActor = new Lang.Class({
     Name: 'SourceActor',