[gjs: 1/2] overrides/Gtk: Make GTK4 widgets iteratable

[Philip Chimento <pchimento src gnome org>]

commit 995dde5ffee371da1daf6b62926e072dc1983924
Author: Florian Müllner <fmuellner gnome org>
Date:   Tue May 19 21:56:08 2020 +0200

    overrides/Gtk: Make GTK4 widgets iteratable
    
    GTK4 removed the Gtk.Container interface, and added API on Gtk.Widget
    to iterate over children instead. While that API is perfectly fine
    to use from javascript, implementing the iterable protocol allows
    for a more idiomatic use like
    
      for (let child of widget)
          doStuff(child);
    
    and also provides a convenient replacement for the removed get_children()
    method:
    
      const children = [...widget];

 modules/core/overrides/Gtk.js | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/modules/core/overrides/Gtk.js b/modules/core/overrides/Gtk.js
index 9839c0ba..a1e85314 100644
--- a/modules/core/overrides/Gtk.js
+++ b/modules/core/overrides/Gtk.js
@@ -125,6 +125,13 @@ function _init() {
         return klass;
     };
 
+    if (Gtk.Widget.prototype.get_first_child) {
+        Gtk.Widget.prototype[Symbol.iterator] = function* () {
+            for (let c = this.get_first_child(); c; c = c.get_next_sibling())
+                yield c;
+        };
+    }
+
     if (Gtk.BuilderScope) {
         BuilderScope = GObject.registerClass({
             Implements: [Gtk.BuilderScope],