MD WebUI: Move history-lazy-render into cr-elements

chrome/browser/resources/md_history/lazy_render.js

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-/**
- * @fileoverview
- * history-lazy-render is a simple variant of dom-if designed for lazy rendering
- * of elements that are accessed imperatively.
- * Usage:
- *   <template is="history-lazy-render" id="menu">
- *     <heavy-menu></heavy-menu>
- *   </template>
- *
- *   this.$.menu.get().then(function(menu) {
- *     menu.show();
- *   });
- */
-
-Polymer({
-  is: 'history-lazy-render',
-  extends: 'template',
-
-  behaviors: [
-    Polymer.Templatizer
-  ],
-
-  /** @private {Promise<Element>} */
-  _renderPromise: null,
-
-  /** @private {TemplateInstance} */
-  _instance: null,
-
-  /**
-   * Stamp the template into the DOM tree asynchronously
-   * @return {Promise<Element>} Promise which resolves when the template has
-   *   been stamped.
-   */
-  get: function() {
-    if (!this._renderPromise) {
-      this._renderPromise = new Promise(function(resolve) {
-        this._debounceTemplate(function() {
-          this._render();
-          this._renderPromise = null;
-          resolve(this.getIfExists());
-        }.bind(this));
-      }.bind(this));
-    }
-    return this._renderPromise;
-  },
-
-  /**
-   * @return {?Element} The element contained in the template, if it has
-   *   already been stamped.
-   */
-  getIfExists: function() {
-    if (this._instance) {
-      var children = this._instance._children;
-
-      for (var i = 0; i < children.length; i++) {
-        if (children[i].nodeType == Node.ELEMENT_NODE)
-          return children[i];
-      }
-    }
-    return null;
-  },
-
-  _render: function() {
-    if (!this.ctor)
-      this.templatize(this);
-    var parentNode = this.parentNode;
-    if (parentNode && !this._instance) {
-      this._instance = /** @type {TemplateInstance} */(this.stamp({}));
-      var root = this._instance.root;
-      parentNode.insertBefore(root, this);
-    }
-  },
-
-  /**
-   * @param {string} prop
-   * @param {Object} value
-   */
-  _forwardParentProp: function(prop, value) {
-    if (this._instance)
-      this._instance.__setProperty(prop, value, true);
-  },
-
-  /**
-   * @param {string} path
-   * @param {Object} value
-   */
-  _forwardParentPath: function(path, value) {
-    if (this._instance)
-      this._instance._notifyPath(path, value, true);
-  }
-});