[gnome-shell] dialog: Check whether text changed when setting title or description

[Florian Müllner <fmuellner src gnome org>]

commit e4bb2037ca16a7f6fff06f1e28fd633f5bb0048f
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Sun Jun 28 13:06:26 2020 +0200

    dialog: Check whether text changed when setting title or description
    
    As usually with GObject setters, we should check whether the property
    actually changed before setting the value and notifying the property. So
    check whether the title or description text actually changed before
    setting it.
    
    This fixes a bug which makes the title flicker and change its size,
    because when updating the title we remove the "leightweight" css class
    and reapply it inside a later, which makes the title appear larger for
    one frame.
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2574
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1336

 js/ui/dialog.js | 6 ++++++
 1 file changed, 6 insertions(+)
---
diff --git a/js/ui/dialog.js b/js/ui/dialog.js
index dacdf3d399..8e9fb50908 100644
--- a/js/ui/dialog.js
+++ b/js/ui/dialog.js
@@ -228,6 +228,9 @@ var MessageDialogContent = GObject.registerClass({
     }
 
     set title(title) {
+        if (this._title.text === title)
+            return;
+
         _setLabel(this._title, title);
 
         this._title.remove_style_class_name('leightweight');
@@ -237,6 +240,9 @@ var MessageDialogContent = GObject.registerClass({
     }
 
     set description(description) {
+        if (this._description.text === description)
+            return;
+
         _setLabel(this._description, description);
         this.notify('description');
     }