[gnome-shell/gbsneto/icon-grid-dnd] baseAppView: Add only non-added icons, in order

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d6a2e8cdad1cbb2caf41e06cd79e466408da4589
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Jul 1 23:01:59 2019 -0300

    baseAppView: Add only non-added icons, in order
    
    In the close future, BaseAppView will only add new icons (compared
    to the remove all + readd all approach that is now). With that, the
    items in the this._allItems array will be iterated multiple times,
    but items can only be added once, and in the order they're in the
    array.
    
    Add the items in the this._allItems array passing the index they
    should be added, and don't add icons with a parent already set.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/603

 js/ui/appDisplay.js | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 35cca0a05..a8a4d59ed 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -147,7 +147,17 @@ class BaseAppView {
 
     _loadGrid() {
         this._allItems.sort(this._compareItems);
-        this._allItems.forEach(item => { this._grid.addItem(item); });
+
+        for (let i = 0; i < this._allItems.length; i++) {
+            let item = this._allItems[i];
+
+            // Don't readd already added items
+            if (item.actor.get_parent())
+                continue;
+
+            this._grid.addItem(item, i);
+        }
+
         this.emit('view-loaded');
     }