[gnome-shell] keyboard: Only rebuild keyboard actor on keyboard type changes

[Carlos Garnacho <carlosg src gnome org>]

commit 08ad345f234ae7af4798da9aa60c35f37208d02f
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Jul 23 13:51:11 2017 +0200

    keyboard: Only rebuild keyboard actor on keyboard type changes
    
    About every other situation can do with synchronizing keyboard visibility,
    and keyboard layout changes are already handled internally in the Keyboard
    object.
    
    A downside of this approach is that once created, there will always be a
    Keyboard instance and its full actor hierarchy. Seems reasonable to do that
    since we can't tell it won't ever be needed.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=785309

 js/ui/keyboard.js |   30 +++++++++++++++++++-----------
 1 files changed, 19 insertions(+), 11 deletions(-)
---
diff --git a/js/ui/keyboard.js b/js/ui/keyboard.js
index a0732f5..da36c36 100644
--- a/js/ui/keyboard.js
+++ b/js/ui/keyboard.js
@@ -171,7 +171,7 @@ var Keyboard = new Lang.Class({
         this._keyboardSettings = new Gio.Settings({ schema_id: KEYBOARD_SCHEMA });
         this._keyboardSettings.connect('changed', Lang.bind(this, this._sync));
         this._a11yApplicationsSettings = new Gio.Settings({ schema_id: A11Y_APPLICATIONS_SCHEMA });
-        this._a11yApplicationsSettings.connect('changed', Lang.bind(this, this._sync));
+        this._a11yApplicationsSettings.connect('changed', Lang.bind(this, this._syncEnabled));
         this._lastDeviceId = null;
 
         Caribou.DisplayAdapter.set_default(new LocalAdapter());
@@ -183,7 +183,7 @@ var Keyboard = new Lang.Class({
 
                 if (device.get_device_name().indexOf('XTEST') < 0) {
                     this._lastDeviceId = deviceId;
-                    this._sync();
+                    this._syncEnabled();
                 }
             }));
         this._sync();
@@ -304,24 +304,32 @@ var Keyboard = new Lang.Class({
         return device.get_device_type() == Clutter.InputDeviceType.TOUCHSCREEN_DEVICE;
     },
 
-    _sync: function () {
+    _syncEnabled: function () {
         this._enableKeyboard = this._a11yApplicationsSettings.get_boolean(SHOW_KEYBOARD) ||
                                this._lastDeviceIsTouchscreen();
         if (!this._enableKeyboard && !this._keyboard)
             return;
-        if (this._enableKeyboard && this._keyboard &&
-            this._keyboard.keyboard_type == this._keyboardSettings.get_string(KEYBOARD_TYPE))
-            return;
 
         this._setCaretTrackerEnabled(this._enableKeyboard);
 
-        if (this._keyboard)
-            this._destroyKeyboard();
+        if (this._enableKeyboard) {
+            if (!this._keyboard)
+                this._setupKeyboard();
+            else
+                Main.layoutManager.showKeyboard();
+        } else {
+            Main.layoutManager.hideKeyboard(true);
+        }
+    },
 
-        if (this._enableKeyboard)
+    _sync: function () {
+        if (this._keyboard &&
+            this._keyboard.keyboard_type != this._keyboardSettings.get_string(KEYBOARD_TYPE)) {
+            this._destroyKeyboard();
             this._setupKeyboard();
-        else
-            Main.layoutManager.hideKeyboard(true);
+        }
+
+        this._syncEnabled();
     },
 
     _destroyKeyboard: function() {