switcherPopup: Move _createSwitcher implementations into constructors

We don't really need this step as a separate method since all
implementations are supposed to be created and shown immediately. This
also ensures that we have items to show in all subclasses.

https://bugzilla.gnome.org/show_bug.cgi?id=735976

js/ui/altTab.js

@@ -58,6 +58,14 @@ const AppSwitcherPopup = new Lang.Class({
         this._currentWindow = -1;
 
         this.thumbnailsVisible = false;
+
+        let apps = Shell.AppSystem.get_default().get_running ();
+
+        if (apps.length == 0)
+            return;
+
+        this._switcherList = new AppSwitcher(apps, this);
+        this._items = this._switcherList.icons;
     },
 
     _allocate: function (actor, box, flags) {
@@ -99,20 +107,6 @@ const AppSwitcherPopup = new Lang.Class({
         }
     },
 
-    _createSwitcher: function() {
-        let apps = Shell.AppSystem.get_default().get_running ();
-
-        if (apps.length == 0)
-            return false;
-
-        this._switcherList = new AppSwitcher(apps, this);
-        this._items = this._switcherList.icons;
-        if (this._items.length == 0)
-            return false;
-
-        return true;
-    },
-
     _initialSelection: function(backward, binding) {
         if (binding == 'switch-group') {
             if (backward) {
@@ -365,9 +359,18 @@ const WindowSwitcherPopup = new Lang.Class({
     Name: 'WindowSwitcherPopup',
     Extends: SwitcherPopup.SwitcherPopup,
 
-    _init: function(items) {
+    _init: function() {
-        this.parent(items);
+        this.parent();
         this._settings = new Gio.Settings({ schema_id: 'org.gnome.shell.window-switcher' });
+
+        let windows = this._getWindowList();
+
+        if (windows.length == 0)
+            return;
+
+        let mode = this._settings.get_enum('app-icon-mode');
+        this._switcherList = new WindowList(windows, mode);
+        this._items = this._switcherList.icons;
     },
 
     _getWindowList: function() {
@@ -375,22 +378,6 @@ const WindowSwitcherPopup = new Lang.Class({
         return global.display.get_tab_list(Meta.TabList.NORMAL, workspace);
     },
 
-    _createSwitcher: function() {
-        let windows = this._getWindowList();
-
-        if (windows.length == 0)
-            return false;
-
-        let mode = this._settings.get_enum('app-icon-mode');
-        this._switcherList = new WindowList(windows, mode);
-        this._items = this._switcherList.icons;
-
-        if (this._items.length == 0)
-            return false;
-
-        return true;
-    },
-
     _initialSelection: function(backward, binding) {
         if (binding == 'switch-windows-backward' || backward)
             this._select(this._items.length - 1);

js/ui/ctrlAltTab.js

@@ -140,9 +140,10 @@ const CtrlAltTabPopup = new Lang.Class({
     Name: 'CtrlAltTabPopup',
     Extends: SwitcherPopup.SwitcherPopup,
 
-    _createSwitcher: function() {
+    _init: function(items) {
+        this.parent(items);
+
         this._switcherList = new CtrlAltTabSwitcher(this._items);
-        return true;
     },
 
     _initialSelection: function(backward, binding) {

js/ui/status/keyboard.js

@@ -265,11 +265,8 @@ const InputSourcePopup = new Lang.Class({
 
         this._action = action;
         this._actionBackward = actionBackward;
-    },
 
-    _createSwitcher: function() {
         this._switcherList = new InputSourceSwitcher(this._items);
-        return true;
     },
 
     _initialSelection: function(backward, binding) {

js/ui/switcherPopup.js

@@ -102,16 +102,12 @@ const SwitcherPopup = new Lang.Class({
         this._switcherList.actor.allocate(childBox, flags);
     },
 
-    _createSwitcher: function() {
-        throw new Error('Not implemented');
-    },
-
     _initialSelection: function(backward, binding) {
         throw new Error('Not implemented');
     },
 
     show: function(backward, binding, mask) {
-        if (!this._createSwitcher())
+        if (this._items.length == 0)
             return false;
 
         if (!Main.pushModal(this.actor)) {