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

Source/devtools/front_end/audits/AuditsPanel.js

 /*
  * Copyright (C) 2012 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 25 matching lines @@
 {
     WebInspector.PanelWithSidebar.call(this, "audits");
     this.registerRequiredCSS("ui/panelEnablerView.css");
     this.registerRequiredCSS("audits/auditsPanel.css");
 
     var sidebarTree = new TreeOutline();
     sidebarTree.element.classList.add("sidebar-tree");
     this.panelSidebarElement().appendChild(sidebarTree.element);
     this.setDefaultFocusedElement(sidebarTree.element);
 
-    this.auditsTreeElement = new WebInspector.SidebarSectionTreeElement("", true);
+    this.auditsTreeElement = new WebInspector.SidebarSectionTreeElement("");
     sidebarTree.appendChild(this.auditsTreeElement);
     this.auditsTreeElement.listItemElement.classList.add("hidden");
 
     this.auditsItemTreeElement = new WebInspector.AuditsSidebarTreeElement(this);
     this.auditsTreeElement.appendChild(this.auditsItemTreeElement);
 
-    this.auditResultsTreeElement = new WebInspector.SidebarSectionTreeElement(WebInspector.UIString("RESULTS"), true);
+    this.auditResultsTreeElement = new WebInspector.SidebarSectionTreeElement(WebInspector.UIString("RESULTS"));
     sidebarTree.appendChild(this.auditResultsTreeElement);
     this.auditResultsTreeElement.expand();
 
     this._constructCategories();
 
     this._auditController = new WebInspector.AuditController(this);
     this._launcherView = new WebInspector.AuditLauncherView(this._auditController);
     for (var id in this.categoriesById)
         this._launcherView.addCategory(this.categoriesById[id]);
 
@@ skipping 511 matching lines @@
 }
 
 // Contributed audit rules should go into this namespace.
 WebInspector.AuditRules = {};
 
 /**
  * Contributed audit categories should go into this namespace.
  * @type {!Object.<string, function(new:WebInspector.AuditCategory)>}
  */
 WebInspector.AuditCategories = {};