[gnome-shell] WorkspacesView: don't access the allocation 4 times

[Giovanni Campagna <gcampagna src gnome org>]

commit 37ef0e4bedec57d9e877e4ef3bb5065515bf77d6
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Thu May 8 19:17:26 2014 +0200

    WorkspacesView: don't access the allocation 4 times
    
    Access it once, and save 3 GObject property accesses and related
    copies.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=729823

 js/ui/workspacesView.js |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/js/ui/workspacesView.js b/js/ui/workspacesView.js
index 3dfbe1e..61df6ab 100644
--- a/js/ui/workspacesView.js
+++ b/js/ui/workspacesView.js
@@ -606,8 +606,9 @@ const WorkspacesDisplay = new Lang.Class({
             return;
 
         let [x, y] = this.actor.get_transformed_position();
-        let width = this.actor.allocation.x2 - this.actor.allocation.x1;
-        let height = this.actor.allocation.y2 - this.actor.allocation.y1;
+        let allocation = this.actor.allocation;
+        let width = allocation.x2 - allocation.x1;
+        let height = allocation.y2 - allocation.y1;
         let primaryGeometry = { x: x, y: y, width: width, height: height };
 
         let monitors = Main.layoutManager.monitors;