messageTray: add close button to notifications

Displaying a close button provides a discoverable way to close notifications.
Clicking the close button on new notifications, dismisses them, but doesn't
remove the notification source from the message tray if it is resident.

Clicking the close button on summary notifications acts the same way as clicking
"Remove" option in the right click menu, which is to remove the notification
stack and its source, even if it is resident or a tray icon.

js/ui/messageTray.js

@@ -1160,6 +1160,14 @@ const SummaryItem = new Lang.Class({
         this._sourceBox.add(this._sourceIcon, { y_fill: false });
         this.actor.child = this._sourceBox;
 
+        this._closeButton = new St.Button({ style_class: 'window-close' });
+        this._closeButton.connect('clicked', Lang.bind(this, function() {
+            source.destroy();
+            this.emit('done-displaying-content');
+        }));
+
+        this.notificationStackWidget = new St.Widget();
+        this.notificationStackWidget.add_actor(this._closeButton);
         this.notificationStackView = new St.ScrollView({ style_class: source.isChat ? '' : 'summary-notification-stack-scrollview',
                                                          vscrollbar_policy: source.isChat ? Gtk.PolicyType.NEVER : Gtk.PolicyType.AUTOMATIC,
                                                          hscrollbar_policy: Gtk.PolicyType.NEVER });
@@ -1167,6 +1175,7 @@ const SummaryItem = new Lang.Class({
         this.notificationStack = new St.BoxLayout({ style_class: 'summary-notification-stack',
                                                     vertical: true });
         this.notificationStackView.add_actor(this.notificationStack);
+        this.notificationStackWidget.add_actor(this.notificationStackView);
         this._stackedNotifications = [];
 
         this._oldMaxScrollAdjustment = 0;
@@ -1219,6 +1228,13 @@ const SummaryItem = new Lang.Class({
         for (let i = 0; i < this.source.notifications.length; i++) {
             this._appendNotificationToStack(this.source.notifications[i]);
         }
+
+        let closeNode = this._closeButton.get_theme_node();
+        let overlap = closeNode.get_length('-shell-close-overlap');
+        this.notificationStackWidget.width = this.notificationStackView.width;
+        this._closeButton.x = this.notificationStackView.width - overlap;
+        this._closeButton.y = - overlap;
+        this.scrollTo(St.Side.BOTTOM);
     },
 
     doneShowingNotificationStack: function() {
@@ -1357,6 +1373,11 @@ const MessageTray = new Lang.Class({
         this._clickedSummaryItemAllocationChangedId = 0;
         this._pointerBarrier = 0;
 
+        this._closeButton = new St.Button({ style_class: 'window-close' });
+        this.actor.add_actor(this._closeButton);
+        this._closeButton.hide();
+        this._closeButton.connect('clicked', Lang.bind(this, this._onCloseClicked));
+
         this._idleMonitorWatchId = 0;
         this._userActiveWhileNotificationShown = false;
 
@@ -1406,6 +1427,7 @@ const MessageTray = new Lang.Class({
         this.actor.y = 0;
         Main.layoutManager.trackChrome(this.actor);
         Main.layoutManager.trackChrome(this._notificationBin);
+        Main.layoutManager.trackChrome(this._closeButton);
 
         Main.layoutManager.connect('monitors-changed', Lang.bind(this, this._setSizePosition));
         Main.layoutManager.connect('primary-fullscreen-changed', Lang.bind(this, this._onFullscreenChanged));
@@ -1437,6 +1459,14 @@ const MessageTray = new Lang.Class({
         this._chatSummaryItemsCount = 0;
     },
 
+    _onCloseClicked: function() {
+        if (this._notificationState == State.SHOWN) {
+            this._notification.emit('done-displaying');
+                if (!this._notification.resident)
+                    this._notification.destroy();
+        }
+    },
+
     _onCornerEnter: function(actor, event) {
         this._traySummoned = true;
         this._updateState();
@@ -1853,7 +1883,7 @@ const MessageTray = new Lang.Class({
         // to show notifications for legacy tray icons, but this would be necessary if we did.
         let requestedNotificationStackIsEmpty = (this._clickedSummaryItemMouseButton == 1 && this._clickedSummaryItem.source.notifications.length == 0);
         let wrongSummaryNotificationStack = (this._clickedSummaryItemMouseButton == 1 &&
-                                             this._summaryBoxPointer.bin.child != this._clickedSummaryItem.notificationStackView);
+                                             this._summaryBoxPointer.bin.child != this._clickedSummaryItem.notificationStackWidget);
         let wrongSummaryRightClickMenu = (this._clickedSummaryItemMouseButton == 3 &&
                                           this._summaryBoxPointer.bin.child != this._clickedSummaryItem.rightClickMenu);
         let wrongSummaryBoxPointer = (haveClickedSummaryItem &&
@@ -2121,6 +2151,8 @@ const MessageTray = new Lang.Class({
             this._notificationBin.y = this.actor.height;
             this._notificationBin.opacity = 0;
             this._notificationState = State.HIDDEN;
+            this._closeButton.y = this.actor.height;
+            this._closeButton.opacity = 0;
             this._hideNotificationCompleted();
         } else {
             this._tween(this._notificationBin, '_notificationState', State.HIDDEN,
@@ -2131,12 +2163,20 @@ const MessageTray = new Lang.Class({
                           onComplete: this._hideNotificationCompleted,
                           onCompleteScope: this
                         });
+
+            Tweener.addTween(this._closeButton,
+                             { y: this.actor.height,
+                               opacity: 0,
+                               time: ANIMATION_TIME,
+                               transition: 'easeOutQuad',
+                             });
         }
     },
 
     _hideNotificationCompleted: function() {
         this._notificationRemoved = false;
         this._notificationBin.hide();
+        this._closeButton.hide();
         this._pointerInTray = false;
         this._notificationBin.child = null;
         this._notification.collapseCompleted();
@@ -2164,19 +2204,39 @@ const MessageTray = new Lang.Class({
 
     _onNotificationExpanded: function() {
         let expandedY = - this._notificationBin.height;
+        let closeNode = this._closeButton.get_theme_node();
+        let overlap = closeNode.get_length('-shell-close-overlap');
+        // In case when we expand the urgent notification right away, this._notification.actor
+        // is not allocated yet, so we need to allocate it to be able to get the right value
+        // for this._notification.actor.x
+        this._notification.actor.get_allocation_box();
+        this._closeButton.x = (this._notification.actor.x + this._notification.actor.width) - overlap;
+        this._closeButton.opacity = this._notificationBin.opacity;
+        this._closeButton.show();
 
         // Don't animate the notification to its new position if it has shrunk:
         // there will be a very visible "gap" that breaks the illusion.
 
-        if (this._notificationBin.y < expandedY)
+        if (this._notificationBin.y < expandedY) {
             this._notificationBin.y = expandedY;
-        else if (this._notification.y != expandedY)
+            this._closeButton.y = expandedY - overlap;
+        } else if (this._notification.y != expandedY) {
+            this._closeButton.y = this._notificationBin.y - overlap;
             this._tween(this._notificationBin, '_notificationState', State.SHOWN,
                         { y: expandedY,
                           time: ANIMATION_TIME,
                           transition: 'easeOutQuad'
                         });
-   },
+            Tweener.addTween(this._closeButton,
+                             { y: expandedY - overlap,
+                               opacity: 255,
+                               time: ANIMATION_TIME,
+                               transition: 'easeOutQuad'
+                             });
+        } else {
+             this._closeButton.y = expandedY - overlap;
+        }
+    },
 
     // We use this function to grab focus when the user moves the pointer
     // to a notification with CRITICAL urgency that was already auto-expanded.
@@ -2222,9 +2282,8 @@ const MessageTray = new Lang.Class({
             }
             this._notificationQueue = newQueue;
 
+            this._summaryBoxPointer.bin.child = this._summaryBoxPointerItem.notificationStackWidget;
             this._summaryBoxPointerItem.prepareNotificationStackForShowing();
-            this._summaryBoxPointer.bin.child = this._summaryBoxPointerItem.notificationStackView;
-            this._summaryBoxPointerItem.scrollTo(St.Side.BOTTOM);
         } else if (this._clickedSummaryItemMouseButton == 3) {
             this._summaryBoxPointer.bin.child = this._clickedSummaryItem.rightClickMenu;
         }
@@ -2321,7 +2380,7 @@ const MessageTray = new Lang.Class({
     },
 
     _hideSummaryBoxPointerCompleted: function() {
-        let doneShowingNotificationStack = (this._summaryBoxPointer.bin.child == this._summaryBoxPointerItem.notificationStackView);
+        let doneShowingNotificationStack = (this._summaryBoxPointer.bin.child == this._summaryBoxPointerItem.notificationStackWidget);
 
         this._summaryBoxPointerState = State.HIDDEN;
         this._summaryBoxPointer.bin.child = null;