[gnome-shell] Fix negative height request in WellGrid

[Siegfried-Angel Gevatter Pujals <sgevatter src gnome org>]

commit 4495f98dcec83c2726cedf9aba5afd3c1d97ddea
Author: Siegfried-Angel Gevatter Pujals <rainct ubuntu com>
Date:   Sun Aug 9 03:34:35 2009 +0200

    Fix negative height request in WellGrid
    
    When WellGrid had no child it was doing a division by zero,
    which screwed up the calculation for the height request and
    having it ask for a negative number. This commit fixes this
    by always requesting 0 in this case.

 js/ui/appDisplay.js |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index f992404..1558f71 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -686,6 +686,8 @@ WellGrid.prototype = {
         let columnsNatural;
         let i;
         let children = this._getItemChildren();
+        if (children.length == 0)
+            return [0, WELL_DEFAULT_COLUMNS, 0, 0];
         let nColumns;
         if (children.length < WELL_DEFAULT_COLUMNS)
             nColumns = children.length;