[gnome-shell/wip/carlosg/avoid-keymap-reloads] keyboardManager: Avoid idempotent calls to meta_backend_set_keymap()

[Carlos Garnacho <carlosg src gnome org>]

commit d86949919901885f0494acb1d4e0db0dccf59545
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Oct 23 00:06:36 2018 +0200

    keyboardManager: Avoid idempotent calls to meta_backend_set_keymap()
    
    But still try to apply the keymap whenever the input sources changed. This
    is a different approach to gnome-shell#240 that still avoid redundant
    changes to the current keymap, but actually trigger one when input sources
    are added.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1637418
    
    Closes: https://gitlab.gnome.org/GNOME/gnome-shell/issues/691

 js/misc/keyboardManager.js | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)
---
diff --git a/js/misc/keyboardManager.js b/js/misc/keyboardManager.js
index ae59f0014..f4001f130 100644
--- a/js/misc/keyboardManager.js
+++ b/js/misc/keyboardManager.js
@@ -52,11 +52,20 @@ var KeyboardManager = new Lang.Class({
         this._current = null;
         this._localeLayoutInfo = this._getLocaleLayout();
         this._layoutInfos = {};
+        this._currentKeymap = null;
     },
 
     _applyLayoutGroup(group) {
         let options = this._buildOptionsString();
         let [layouts, variants] = this._buildGroupStrings(group);
+
+        if (this._currentKeymap &&
+            this._currentKeymap.layouts == layouts &&
+            this._currentKeymap.variants == variants &&
+            this._currentKeymap.options == options)
+            return;
+
+        this._currentKeymap = {layouts, variants, options};
         Meta.get_backend().set_keymap(layouts, variants, options);
     },
 
@@ -89,8 +98,6 @@ var KeyboardManager = new Lang.Class({
     },
 
     setUserLayouts(ids) {
-        let currentId = this._current ? this._current.id : null;
-        let currentGroupIndex = this._current ? this._current.groupIndex : null;
         this._current = null;
         this._layoutInfos = {};
 
@@ -117,9 +124,6 @@ var KeyboardManager = new Lang.Class({
             info.group = group;
             info.groupIndex = groupIndex;
 
-            if (currentId == id && currentGroupIndex == groupIndex)
-                this._current = info;
-
             i += 1;
         }
     },