dnd: Avoid division by zero, etc for zero-size actors

When rescaling due to a possible parent actor resize avoid problems
if the parent width is zero.

https://bugzilla.gnome.org/show_bug.cgi?id=643786

diff --git a/js/ui/dnd.js b/js/ui/dnd.js
index a755057f1b71967ea4be56f07d9366656088d31d..87515563fd5ed7ccb53cf30d40fac5ac91fd52aa 100644 (file)
--- a/js/ui/dnd.js
+++ b/js/ui/dnd.js
@@ -480,7 +480,9 @@ _Draggable.prototype = {
             let [parentX, parentY] = this._dragOrigParent.get_transformed_position();
             let [parentWidth, parentHeight] = this._dragOrigParent.get_size();
             let [parentScaledWidth, parentScaledHeight] = this._dragOrigParent.get_transformed_size();
-            let parentScale = parentScaledWidth / parentWidth;
+            let parentScale = 1.0;
+            if (parentWidth != 0)
+                parentScale = parentScaledWidth / parentWidth;
 
             x = parentX + parentScale * this._dragOrigX;
             y = parentY + parentScale * this._dragOrigY;