shell/global: Add 'backend' property

Replace all Meta.get_backend() with global.backend. Maybe sooner or
later we can further decrease the amount of singletons handled by
libmutter.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1210

js/misc/keyboardManager.js

@@ -1,7 +1,7 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 /* exported getKeyboardManager, holdKeyboard, releaseKeyboard */
 
-const { GLib, GnomeDesktop, Meta } = imports.gi;
+const { GLib, GnomeDesktop } = imports.gi;
 
 const Main = imports.ui.main;
 
@@ -62,11 +62,11 @@ var KeyboardManager = class {
             return;
 
         this._currentKeymap = { layouts, variants, options };
-        Meta.get_backend().set_keymap(layouts, variants, options);
+        global.backend.set_keymap(layouts, variants, options);
     }
 
     _applyLayoutGroupIndex(idx) {
-        Meta.get_backend().lock_layout_group(idx);
+        global.backend.lock_layout_group(idx);
     }
 
     apply(id) {

js/ui/keyboard.js

@@ -1119,7 +1119,7 @@ var KeyboardManager = class KeyBoardManager {
         this._seat.connect('notify::touch-mode', this._syncEnabled.bind(this));
 
         this._lastDevice = null;
-        Meta.get_backend().connect('last-device-changed', (backend, device) => {
+        global.backend.connect('last-device-changed', (backend, device) => {
             if (device.device_type === Clutter.InputDeviceType.KEYBOARD_DEVICE)
                 return;
 

js/ui/main.js

@@ -802,7 +802,7 @@ function showRestartMessage(message) {
 
 var AnimationsSettings = class {
     constructor() {
-        let backend = Meta.get_backend();
+        let backend = global.backend;
         if (!backend.is_rendering_hardware_accelerated()) {
             St.Settings.get().inhibit_animations();
             return;

js/ui/status/remoteAccess.js

@@ -11,8 +11,7 @@ class RemoteAccessApplet extends PanelMenu.SystemIndicator {
     _init() {
         super._init();
 
-        let backend = Meta.get_backend();
+        let controller = global.backend.get_remote_access_controller();
-        let controller = backend.get_remote_access_controller();
 
         if (!controller)
             return;

js/ui/xdndHandler.js

@@ -1,6 +1,6 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 
-const { Clutter, Meta } = imports.gi;
+const { Clutter } = imports.gi;
 const Signals = imports.signals;
 
 const DND = imports.ui.dnd;
@@ -17,7 +17,7 @@ var XdndHandler = class {
         Main.uiGroup.add_actor(this._dummy);
         this._dummy.hide();
 
-        var dnd = Meta.get_backend().get_dnd();
+        var dnd = global.backend.get_dnd();
         dnd.connect('dnd-enter', this._onEnter.bind(this));
         dnd.connect('dnd-position-change', this._onPositionChanged.bind(this));
         dnd.connect('dnd-leave', this._onLeave.bind(this));

src/shell-global.c

@@ -57,6 +57,7 @@ struct _ShellGlobal {
 
   ClutterStage *stage;
 
+  MetaBackend *backend;
   MetaDisplay *meta_display;
   MetaWorkspaceManager *workspace_manager;
   Display *xdisplay;
@@ -95,6 +96,7 @@ enum {
   PROP_0,
 
   PROP_SESSION_MODE,
+  PROP_BACKEND,
   PROP_DISPLAY,
   PROP_WORKSPACE_MANAGER,
   PROP_SCREEN_WIDTH,
@@ -230,6 +232,9 @@ shell_global_get_property(GObject         *object,
     case PROP_SESSION_MODE:
       g_value_set_string (value, shell_global_get_session_mode (global));
       break;
+    case PROP_BACKEND:
+      g_value_set_object (value, global->backend);
+      break;
     case PROP_DISPLAY:
       g_value_set_object (value, global->meta_display);
       break;
@@ -472,6 +477,13 @@ shell_global_class_init (ShellGlobalClass *klass)
                                                      "Screen height, in pixels",
                                                      0, G_MAXINT, 1,
                                                      G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (gobject_class,
+                                   PROP_BACKEND,
+                                   g_param_spec_object ("backend",
+                                                        "Backend",
+                                                        "MetaBackend object",
+                                                        META_TYPE_BACKEND,
+                                                        G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
   g_object_class_install_property (gobject_class,
                                    PROP_DISPLAY,
                                    g_param_spec_object ("display",
@@ -947,6 +959,7 @@ _shell_global_set_plugin (ShellGlobal *global,
   g_return_if_fail (SHELL_IS_GLOBAL (global));
   g_return_if_fail (global->plugin == NULL);
 
+  global->backend = meta_get_backend ();
   global->plugin = plugin;
   global->wm = shell_wm_new (plugin);