Use wtLayout instead of jQuery.data

jQuery.data (jQuery 1.x) prevents leaks *only* when also using jQuery's
own remove(), html(), etc. functions.

jQuery.data (jQuery 1.x) actually *causes* leaks on modern browsers,
when jQuery's methods are not used, like when calling Node.removeChild()
directly.

Circular references between DOM elements and JS objects are not an issue
with more recent browsers.

(Alternative could be to use ECMAScript 6 WeakMap, which is not
supported by IE)

src/js/StdGridLayoutImpl2.js

@@ -109,7 +109,7 @@ WT_DECLARE_WT_MEMBER
          resizeHandles: []
        }];
 
-   jQuery.data(document.getElementById(id), 'layout', this);
+   document.getElementById(id).wtLayout = this;
 
    function getItem(id) {
      var i, il;
@@ -781,7 +781,7 @@ WT_DECLARE_WT_MEMBER
        var piw = WT.$(parentItemWidget.id);
        if (piw) {
 	 if (parentItemWidget != piw) {
-	   parent = jQuery.data(piw.parentNode, 'layout');
+	   parent = piw.parentNode.wtLayout;
 	   if (!parent) {
 	     /* The parent item widget is no longer in the DOM. Need a test
 	      * case for that. */
@@ -1592,7 +1592,7 @@ WT_DECLARE_WT_MEMBER
        parentWithWtPS = false;
 
        if (!topLevel) {
-	 parent = jQuery.data(document.getElementById(parentId), 'layout');
+	 parent = document.getElementById(parentId).wtLayout;
 	 parentItemWidget = widget;
 	 parentMargin[HORIZONTAL] = boxMargin(parentItemWidget, HORIZONTAL);
 	 parentMargin[VERTICAL] = boxMargin(parentItemWidget, VERTICAL);
@@ -1615,7 +1615,7 @@ WT_DECLARE_WT_MEMBER
 	   if (p.wtGetPS)
 	     parentWithWtPS = true;
 
-	   var l = jQuery.data(p.parentNode, 'layout');
+	   var l = p.parentNode.wtLayout;
 	   if (l) {
 	     parentItemWidget = p;
 	     parent = l;
@@ -1698,7 +1698,7 @@ WT_DECLARE_APP_MEMBER
 
     this.find = function(id) {
       var el = document.getElementById(id);
-      return el ? jQuery.data(el, 'layout') : null;
+      return el ? el.wtLayout : null;
     };
 
     this.setDirty = function(id) {
@@ -1717,7 +1717,7 @@ WT_DECLARE_APP_MEMBER
       var item = el;
       el = el.parentNode;
       while (el && el != document.body) {
-	var layout = jQuery.data(el, 'layout');
+	var layout = el.wtLayout;
 	if (layout)
 	  layout.setElDirty(item);
 	item = el;

src/js/WDialog.js

@@ -106,7 +106,7 @@ WT_DECLARE_WT_MEMBER
      if (pctMaxWidth !== 0) {
        var ws = WT.windowSize();
 
-       var layout = jQuery.data(layoutContainer.firstChild, 'layout');
+       var layout = layoutContainer.firstChild.wtLayout;
        if (layout && layout.setMaxSize) {
 	 layout.setMaxSize(ws.x * pctMaxWidth / 100,
 			   ws.y * pctMaxHeight / 100);
@@ -263,7 +263,7 @@ WT_DECLARE_WT_MEMBER
      resizeBusy = !done;
      wtResize(el, w, h, true);
 
-     var layout = jQuery.data(layoutContainer.firstChild, 'layout');
+     var layout = layoutContainer.firstChild.wtLayout;
      if (layout && layout.setMaxSize)
         layout.setMaxSize(0, 0);