[gnome-shell] ui: Reset workspace thumbnail porthole on monitor changes

[Jonas Ådahl <jadahl src gnome org>]

commit 4427197343e5facc7e695bebe2f0d74dae1ac666
Author: Shih-Yuan Lee (FourDollars) <fourdollars debian org>
Date:   Fri Jun 9 18:26:11 2017 +0800

    ui: Reset workspace thumbnail porthole on monitor changes
    
    The porthole will not be destroyed when the scale factor changed.
    That makes workspace thumbnail porthole still wrong size in the first
    seeing after the scale factor changed.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011

 js/ui/workspaceThumbnail.js |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index 980ffd6..c5472bb 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -676,6 +676,12 @@ const ThumbnailsBox = new Lang.Class({
         this._settings = new Gio.Settings({ schema_id: OVERRIDE_SCHEMA });
         this._settings.connect('changed::dynamic-workspaces',
             Lang.bind(this, this._updateSwitcherVisibility));
+
+        Main.layoutManager.connect('monitors-changed', Lang.bind(this, function() {
+            this._destroyThumbnails();
+            if (Main.overview.visible)
+                this._createThumbnails();
+        }));
     },
 
     _updateSwitcherVisibility: function() {