DevTools: migrate treeoutline from hasChildren to is/setExpandable().

Source/devtools/front_end/timeline/PaintProfilerView.js

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 337 matching lines @@
 };
 
 /**
   * @constructor
   * @param {!WebInspector.PaintProfilerCommandLogView} ownerView
   * @param {!WebInspector.PaintProfilerLogItem} logItem
   * @extends {TreeElement}
   */
 WebInspector.LogTreeElement = function(ownerView, logItem)
 {
-    TreeElement.call(this);
+    TreeElement.call(this, "", !!this._logItem.params);

[caseq, 2015/03/06 09:35:30]

this._logItem is not set at this point.

     this._logItem = logItem;
     this._ownerView = ownerView;
     this._filled = false;
 }
 
 WebInspector.LogTreeElement.prototype = {
     onattach: function()
     {
         this._update();
-        this.hasChildren = !!this._logItem.params;
     },
 
-    onexpand: function()
+    onpopulate: function()
     {
-        if (this._filled)
-            return;
-        this._filled = true;
         for (var param in this._logItem.params)
             WebInspector.LogPropertyTreeElement._appendLogPropertyItem(this, param, this._logItem.params[param]);
     },
 
     /**
       * @param {!Object<string,*>} param
       * @param {string} name
       * @return {string}
       */
     _paramToString: function(param, name)
@@ skipping 202 matching lines @@
     var method = logItem.method.toTitleCase();
 
     var logItemCategories = WebInspector.PaintProfilerView._initLogItemCategories();
     var result = logItemCategories[method];
     if (!result) {
         result = WebInspector.PaintProfilerView.categories()["misc"];
         logItemCategories[method] = result;
     }
     return result;
 }