DevTools: n^2 -> n while loading heap snapshots and timeline files.

Source/devtools/front_end/common/Progress.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 72 matching lines @@
  * @param {!WebInspector.Progress} parent
  * @extends {WebInspector.Object}
  */
 WebInspector.CompositeProgress = function(parent)
 {
     this._parent = parent;
     this._children = [];
     this._childrenDone = 0;
     this._parent.setTotalWork(1);
     this._parent.setWorked(0);
+    // FIXME: there should be no "progress events"
     parent.addEventListener(WebInspector.Progress.Events.Canceled, this._parentCanceled.bind(this));
 }
 
 WebInspector.CompositeProgress.prototype = {
     _childDone: function()
     {
         if (++this._childrenDone !== this._children.length)
             return;
         this.dispatchEventToListeners(WebInspector.Progress.Events.Done);
         this._parent.done();
     },
 
     _parentCanceled: function()
     {
+        // FIXME: there should be no "progress events"
         this.dispatchEventToListeners(WebInspector.Progress.Events.Canceled);
         for (var i = 0; i < this._children.length; ++i) {
             this._children[i].dispatchEventToListeners(WebInspector.Progress.Events.Canceled);
         }
     },
 
     /**
      * @param {number=} weight
      * @return {!WebInspector.SubProgress}
      */
@@ skipping 54 matching lines @@
         this._composite._parent.setTitle(title);
     },
 
     /**
      * @override
      */
     done: function()
     {
         this.setWorked(this._totalWork);
         this._composite._childDone();
+        // FIXME: there should be no "progress events"
         this.dispatchEventToListeners(WebInspector.Progress.Events.Done);
     },
 
     /**
      * @override
      * @param {number} totalWork
      */
     setTotalWork: function(totalWork)
     {
         this._totalWork = totalWork;
@@ skipping 17 matching lines @@
      * @override
      * @param {number=} worked
      */
     worked: function(worked)
     {
         this.setWorked(this._worked + (worked || 1));
     },
 
     __proto__: WebInspector.Object.prototype
 }
+
+/**
+ * @constructor
+ * @extends {WebInspector.Object}
+ * @implements {WebInspector.Progress}
+ */
+WebInspector.ProgressStub = function()
+{
+}
+
+WebInspector.ProgressStub.prototype = {
+    /**
+     * @override
+     * @return {boolean}
+     */
+    isCanceled: function()
+    {
+        return false;
+    },
+
+    /**
+     * @override
+     * @param {string} title
+     */
+    setTitle: function(title)
+    {
+    },
+
+    /**
+     * @override
+     */
+    done: function()
+    {
+    },
+
+    /**
+     * @override
+     * @param {number} totalWork
+     */
+    setTotalWork: function(totalWork)
+    {
+    },
+
+    /**
+     * @override
+     * @param {number} worked
+     * @param {string=} title
+     */
+    setWorked: function(worked, title)
+    {
+    },
+
+    /**
+     * @override
+     * @param {number=} worked
+     */
+    worked: function(worked)
+    {
+    },
+
+    __proto__: WebInspector.Object.prototype
+}