[gnome-shell] Revert "workspaceThumbnail: rebuild thumbnails if workareas size changed"

[Jonas Ådahl <jadahl src gnome org>]

commit 9a5a4b2206c0914208d2708d54a504c5414582fe
Author: Florian Müllner <fmuellner gnome org>
Date:   Fri Jul 20 17:27:33 2018 +0200

    Revert "workspaceThumbnail: rebuild thumbnails if workareas size changed"
    
    It is unclear what the change was supposed to be fixing, but it
    broke animations of workspace additions and removals, as those
    events trigger the ::workareas-changed signal.
    
    This reverts commit c29bd46e7a7e37a83849df8b3186c84eb46679ac.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/162

 js/ui/workspaceThumbnail.js | 22 +++++-----------------
 1 file changed, 5 insertions(+), 17 deletions(-)
---
diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index cf21e1317..76a7416c3 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -678,7 +678,11 @@ var ThumbnailsBox = new Lang.Class({
         this._settings.connect('changed::dynamic-workspaces',
             this._updateSwitcherVisibility.bind(this));
 
-        Main.layoutManager.connect('monitors-changed', this._rebuildThumbnails.bind(this));
+        Main.layoutManager.connect('monitors-changed', () => {
+            this._destroyThumbnails();
+            if (Main.overview.visible)
+                this._createThumbnails();
+        });
 
         this._switchWorkspaceNotifyId = 0;
         this._nWorkspacesNotifyId = 0;
@@ -881,10 +885,6 @@ var ThumbnailsBox = new Lang.Class({
             Main.overview.connect('windows-restacked',
                                   this._syncStacking.bind(this));
 
-        this._workareasChangedId =
-            global.display.connect('workareas-changed',
-                                   this._rebuildThumbnails.bind(this));
-
         this._targetScale = 0;
         this._scale = 0;
         this._pendingScaleUpdate = false;
@@ -918,24 +918,12 @@ var ThumbnailsBox = new Lang.Class({
             this._syncStackingId = 0;
         }
 
-        if (this._workareasChangedId > 0) {
-            global.display.disconnect(this._workareasChangedId);
-            this._workareasChangedId = 0;
-        }
-
         for (let w = 0; w < this._thumbnails.length; w++)
             this._thumbnails[w].destroy();
         this._thumbnails = [];
         this._porthole = null;
     },
 
-    _rebuildThumbnails() {
-        this._destroyThumbnails();
-
-        if (Main.overview.visible)
-            this._createThumbnails();
-    },
-
     _workspacesChanged() {
         let validThumbnails =
             this._thumbnails.filter(t => t.state <= ThumbnailState.NORMAL);