Main: move the stage hierarchy initialization to LayoutManager

It is cleaner to concentrate all layout and chrome management
in one place, instead of having it scattered around the codebase.

https://bugzilla.gnome.org/show_bug.cgi?id=682429

js/ui/layout.js

@@ -18,6 +18,7 @@ const HOT_CORNER_ACTIVATION_TIMEOUT = 0.5;
 const STARTUP_ANIMATION_TIME = 0.2;
 const KEYBOARD_ANIMATION_TIME = 0.15;
 const PLYMOUTH_TRANSITION_TIME = 1;
+const DEFAULT_BACKGROUND_COLOR = Clutter.Color.from_pixel(0x2e3436ff);
 
 const MonitorConstraint = new Lang.Class({
     Name: 'MonitorConstraint',
@@ -119,6 +120,42 @@ const LayoutManager = new Lang.Class({
 
         this._trackedActors = [];
 
+        // Normally, the stage is always covered so Clutter doesn't need to clear
+        // it; however it becomes visible during the startup animation
+        // See the comment below for a longer explanation
+        global.stage.color = DEFAULT_BACKGROUND_COLOR;
+
+        // Set up stage hierarchy to group all UI actors under one container.
+        this.uiGroup = new Shell.GenericContainer({ name: 'uiGroup' });
+        this.uiGroup.connect('allocate',
+                        function (actor, box, flags) {
+                            let children = actor.get_children();
+                            for (let i = 0; i < children.length; i++)
+                                children[i].allocate_preferred_size(flags);
+                        });
+        this.uiGroup.connect('get-preferred-width',
+                        function(actor, forHeight, alloc) {
+                            let width = global.stage.width;
+                            [alloc.min_size, alloc.natural_size] = [width, width];
+                        });
+        this.uiGroup.connect('get-preferred-height',
+                        function(actor, forWidth, alloc) {
+                            let height = global.stage.height;
+                            [alloc.min_size, alloc.natural_size] = [height, height];
+                        });
+
+        global.window_group.reparent(this.uiGroup);
+
+        // Now, you might wonder why we went through all the hoops to implement
+        // the GDM greeter inside an X11 compositor, to do this at the end...
+        // However, hiding this is necessary to avoid showing the background during
+        // the initial animation, before Gdm.LoginDialog covers everything
+        if (Main.sessionMode.isGreeter)
+            global.window_group.hide();
+
+        global.overlay_group.reparent(this.uiGroup);
+        global.stage.add_child(this.uiGroup);
+
         this.screenShieldGroup = new St.Widget({ name: 'screenShieldGroup',
                                                  visible: false,
                                                  clip_to_allocation: true,
@@ -253,7 +290,7 @@ const LayoutManager = new Lang.Class({
             if (!haveTopLeftCorner)
                 continue;
 
-            let corner = new HotCorner();
+            let corner = new HotCorner(this);
             this._hotCorners.push(corner);
             corner.actor.set_position(cornerX, cornerY);
             this.addChrome(corner.actor);
@@ -475,7 +512,7 @@ const LayoutManager = new Lang.Class({
     // monitor (it will be hidden whenever a fullscreen window is visible,
     // and shown otherwise)
     addChrome: function(actor, params) {
-        Main.uiGroup.add_actor(actor);
+        this.uiGroup.add_actor(actor);
         this._trackActor(actor, params);
     },
 
@@ -526,7 +563,7 @@ const LayoutManager = new Lang.Class({
     //
     // Removes @actor from the chrome
     removeChrome: function(actor) {
-        Main.uiGroup.remove_actor(actor);
+        this.uiGroup.remove_actor(actor);
         this._untrackActor(actor);
     },
 
@@ -545,7 +582,7 @@ const LayoutManager = new Lang.Class({
 
         let actorData = Params.parse(params, defaultParams);
         actorData.actor = actor;
-        actorData.isToplevel = actor.get_parent() == Main.uiGroup;
+        actorData.isToplevel = actor.get_parent() == this.uiGroup;
         actorData.visibleId = actor.connect('notify::visible',
                                             Lang.bind(this, this._queueUpdateRegions));
         actorData.allocationId = actor.connect('notify::allocation',
@@ -581,7 +618,7 @@ const LayoutManager = new Lang.Class({
         } else {
             let i = this._findActor(actor);
             let actorData = this._trackedActors[i];
-            actorData.isToplevel = (newParent == Main.uiGroup);
+            actorData.isToplevel = (newParent == this.uiGroup);
         }
     },
 
@@ -781,7 +818,7 @@ const LayoutManager = new Lang.Class({
 
             if (actorData.affectsInputRegion &&
                 actorData.actor.get_paint_visibility() &&
-                !Main.uiGroup.get_skip_paint(actorData.actor))
+                !this.uiGroup.get_skip_paint(actorData.actor))
                 rects.push(rect);
 
             if (!actorData.affectsStruts)

js/ui/main.js

@@ -38,7 +38,6 @@ const XdndHandler = imports.ui.xdndHandler;
 const Util = imports.misc.util;
 
 const OVERRIDES_SCHEMA = 'org.gnome.shell.overrides';
-const DEFAULT_BACKGROUND_COLOR = Clutter.Color.from_pixel(0x2e3436ff);
 
 let componentManager = null;
 let panel = null;
@@ -112,41 +111,17 @@ function start() {
 
     tracker.connect('startup-sequence-changed', _queueCheckWorkspaces);
 
-    // The stage is always covered so Clutter doesn't need to clear it; however
+    // Setup the stage hierarchy early
-    // the color is used as the default contents for the Mutter root background
+    layoutManager = new Layout.LayoutManager();
-    // actor so set it anyways.
+    // For backward compatibility
-    global.stage.color = DEFAULT_BACKGROUND_COLOR;
+    uiGroup = layoutManager.uiGroup;
-    global.stage.no_clear_hint = true;
-
-    _defaultCssStylesheet = global.datadir + '/theme/gnome-shell.css';
-    loadTheme();
-
-    // Set up stage hierarchy to group all UI actors under one container.
-    uiGroup = new Shell.GenericContainer({ name: 'uiGroup' });
-    uiGroup.connect('allocate',
-                    function (actor, box, flags) {
-                        let children = uiGroup.get_children();
-                        for (let i = 0; i < children.length; i++)
-                            children[i].allocate_preferred_size(flags);
-                    });
-    uiGroup.connect('get-preferred-width',
-                    function(actor, forHeight, alloc) {
-                        let width = global.stage.width;
-                        [alloc.min_size, alloc.natural_size] = [width, width];
-                    });
-    uiGroup.connect('get-preferred-height',
-                    function(actor, forWidth, alloc) {
-                        let height = global.stage.height;
-                        [alloc.min_size, alloc.natural_size] = [height, height];
-                    });
-    global.window_group.reparent(uiGroup);
-    global.overlay_group.reparent(uiGroup);
-    global.stage.add_actor(uiGroup);
 
     let backgroundActor = global.window_group.background;
     background = backgroundActor.settings;
 
-    layoutManager = new Layout.LayoutManager();
+    _defaultCssStylesheet = global.datadir + '/theme/gnome-shell.css';
+    loadTheme();
+
     xdndHandler = new XdndHandler.XdndHandler();
     ctrlAltTabManager = new CtrlAltTab.CtrlAltTabManager();
     overview = new Overview.Overview();

js/ui/panel.js

@@ -644,7 +644,7 @@ const ActivitiesButton = new Lang.Class({
 
         this.actor.label_actor = this._label;
 
-        this.hotCorner = new Layout.HotCorner();
+        this.hotCorner = new Layout.HotCorner(Main.layoutManager);
         container.add_actor(this.hotCorner.actor);
 
         this.actor.connect('captured-event', Lang.bind(this, this._onCapturedEvent));