Added SetHorizontalLayout method

widget/public/nsIToolbar.h

@@ -95,6 +95,12 @@ public:
   */
   NS_IMETHOD DoLayout() = 0;
 
+ /**
+  * Forces the toolbar to layout horizontally
+  *
+  */
+  NS_IMETHOD SetHorizontalLayout(PRBool aDoHorizontalLayout) = 0;
+
  /**
   * Indicates that the last item is right justifed
   *