Remove third_party/polymer from .gitignore

third_party/polymer/v1_0/components/iron-test-helpers/test-helpers.js

-/**
- * @license
- * Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
- * This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
- * The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
- * The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
- * Code distributed by Google as part of the polymer project is also
- * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
- */
-(function(global) {
-
-  global.flushAsynchronousOperations = function() {
-    // force distribution
-    Polymer.dom.flush();
-    // force lifecycle callback to fire on polyfill
-    window.CustomElements && window.CustomElements.takeRecords();
-  };
-
-  global.forceXIfStamp = function(node) {
-    var templates = Polymer.dom(node.root).querySelectorAll('template[is=dom-if]');
-    for (var tmpl, i = 0; tmpl = templates[i]; i++) {
-      tmpl.render();
-    }
-
-    global.flushAsynchronousOperations();
-  };
-
-  global.fireEvent = function(type, props, node) {
-    var event = new CustomEvent(type, {
-      bubbles: true,
-      cancelable: true
-    });
-    for (p in props) {
-      event[p] = props[p];
-    }
-    node.dispatchEvent(event);
-  };
-
-})(this);