[gnome-shell] workspace: Unbreak reposition animation

[Florian Müllner <fmuellner src gnome org>]

commit b2c35e4fb0fdf0d0c692e3eee0aa18547f05a8c2
Author: Florian Müllner <fmuellner gnome org>
Date:   Sun Jun 14 01:02:52 2020 +0200

    workspace: Unbreak reposition animation
    
    Commit 1ea22a5281c broke the window reposition animation when it
    based the ::size-changed signal on the layout manager's bounding box
    instead of the MetaWindow::size-changed signal.
    
    That's happening because of the combination of:
    
      1. we adjust to window size changes immediately without animations
      2. closing a window triggers a change to a 0x0 bounding box which
         is not treated as a size change
    
    Fix this by addressing the 2nd factor, and don't treat a change to
    a 0x0 bounding box as size change.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2901

 js/ui/workspace.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 3367f4d8d9..9d8f8db7a2 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -236,7 +236,11 @@ var WindowClone = GObject.registerClass({
         this._stackAbove = null;
 
         this._windowContainer.layout_manager.connect(
-            'notify::bounding-box', () => this.emit('size-changed'));
+            'notify::bounding-box', layout => {
+                // A bounding box of 0x0 means all windows were removed
+                if (layout.bounding_box.get_area() > 0)
+                    this.emit('size-changed');
+            });
 
         this._windowDestroyId =
             this.realWindow.connect('destroy', () => this.destroy());