[gnome-shell/eos3.8: 143/255] altTab: Make cachedWindows property configurable

[Matthew Leeds <mwleeds src gnome org>]

commit 3a1b80d84f3cf425cb5d69f7851ccc86f687bd84
Author: Andre Moreira Magalhaes <andre endlessm com>
Date:   Fri Mar 27 15:19:03 2020 -0300

    altTab: Make cachedWindows property configurable
    
    This fixes an issue where the hack extension tries to override the
    property and fails with:
      JS ERROR: Extension eos-hack endlessm com: TypeError: can't redefine non-configurable property 
"cachedWindows"
    
    https://phabricator.endlessm.com/T28780

 js/ui/altTab.js | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index 277200c266..15b805867b 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -648,6 +648,8 @@ class AppIcon extends St.BoxLayout {
             x_align: Clutter.ActorAlign.CENTER,
         });
         this.add_child(this.label);
+
+        this._cachedWindows = [];
     }
 
     // eslint-disable-next-line camelcase
@@ -655,6 +657,14 @@ class AppIcon extends St.BoxLayout {
         this.icon = this.app.create_icon_texture(size);
         this._iconBin.child = this.icon;
     }
+
+    get cachedWindows() {
+        return this._cachedWindows;
+    }
+
+    set cachedWindows(windowList) {
+        this._cachedWindows = windowList;
+    }
 });
 
 var AppSwitcher = GObject.registerClass(