DevTools: Improve performance of the element breadcrumbs.

Source/devtools/front_end/treeoutline.js

 /*
  * Copyright (C) 2007 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 33 matching lines @@
     this.hasChildren = false;
     this.expanded = true;
     this.selected = false;
     this.treeOutline = this;
     /** @type {function(TreeElement,TreeElement):number|null} */
     this.comparator = null;
 
     this.setFocusable(!nonFocusable);
     this._childrenListNode.addEventListener("keydown", this._treeKeyDown.bind(this), true);
 
-    /** @type {!Map.<Object, !Array.<!TreeElement>>} */
+    /** @type {!Map.<!Object, !Array.<!TreeElement>>} */
     this._treeElementsMap = new Map();
-    /** @type {!Map.<Object, boolean>} */
+    /** @type {!Map.<!Object, boolean>} */
     this._expandedStateMap = new Map();
 }
 
 TreeOutline.prototype.setFocusable = function(focusable)
 {
     if (focusable)
         this._childrenListNode.setAttribute("tabIndex", 0);
     else
         this._childrenListNode.removeAttribute("tabIndex");
 }
@@ skipping 191 matching lines @@
  */
 TreeOutline.prototype._forgetChildrenRecursive = function(parentElement)
 {
     var child = parentElement.children[0];
     while (child) {
         this._forgetTreeElement(child);
         child = child.traverseNextTreeElement(false, parentElement, true);
     }
 }
 
+/**
+ * @param {Object} representedObject
+ * @return {TreeElement}
+ */
 TreeOutline.prototype.getCachedTreeElement = function(representedObject)
 {
     if (!representedObject)
         return null;
 
     var elements = this._treeElementsMap.get(representedObject);
     if (elements && elements.length)
         return elements[0];
     return null;
 }
 
+/**
+ * @param {Object} representedObject
+ * @return {TreeElement}
+ */
 TreeOutline.prototype.findTreeElement = function(representedObject, isAncestor, getParent)
 {
     if (!representedObject)
         return null;
 
     var cachedElement = this.getCachedTreeElement(representedObject);
     if (cachedElement)
         return cachedElement;
 
     // Walk up the parent pointers from the desired representedObject 
@@ skipping 10 matching lines @@
     // Walk down to populate each ancestor's children, to fill in the tree and the cache.
     for (var i = ancestors.length - 1; i >= 0; --i) {
         var treeElement = this.getCachedTreeElement(ancestors[i]);
         if (treeElement)
             treeElement.onpopulate();  // fill the cache with the children of treeElement
     }
 
     return this.getCachedTreeElement(representedObject);
 }
 
+/**
+ * @param {number} x
+ * @param {number} y
+ * @return {TreeElement}
+ */
 TreeOutline.prototype.treeElementFromPoint = function(x, y)
 {
     var node = this._childrenListNode.ownerDocument.elementFromPoint(x, y);
     if (!node)
         return null;
 
     var listNode = node.enclosingNodeOrSelfWithNodeNameInArray(["ol", "li"]);
     if (listNode)
         return listNode.parentTreeElement || listNode.treeElement;
     return null;
@@ skipping 606 matching lines @@
 }
 
 TreeElement.prototype.isEventWithinDisclosureTriangle = function(event)
 {
     // FIXME: We should not use getComputedStyle(). For that we need to get rid of using ::before for disclosure triangle. (http://webk.it/74446) 
     var paddingLeftValue = window.getComputedStyle(this._listItemNode).getPropertyCSSValue("padding-left");
     var computedLeftPadding = paddingLeftValue ? paddingLeftValue.getFloatValue(CSSPrimitiveValue.CSS_PX) : 0;
     var left = this._listItemNode.totalOffsetLeft() + computedLeftPadding;
     return event.pageX >= left && event.pageX <= left + this.arrowToggleWidth && this.hasChildren;
 }