Remove third_party/polymer from .gitignore

third_party/polymer/v1_0/components/iron-menu-behavior/iron-menu-behavior.html

-<!--
-@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
--->
-
-<link rel="import" href="../polymer/polymer.html">
-<link rel="import" href="../iron-selector/iron-multi-selectable.html">
-<link rel="import" href="../iron-a11y-keys-behavior/iron-a11y-keys-behavior.html">
-
-<script>
-
-  /**
-   * `Polymer.IronMenuBehavior` implements accessible menu behavior.
-   *
-   * @demo demo/index.html
-   * @polymerBehavior Polymer.IronMenuBehavior
-   */
-  Polymer.IronMenuBehaviorImpl = {
-
-    properties: {
-
-      /**
-       * Returns the currently focused item.
-       *
-       * @attribute focusedItem
-       * @type Object
-       */
-      focusedItem: {
-        observer: '_focusedItemChanged',
-        readOnly: true,
-        type: Object
-      },
-
-      /**
-       * The attribute to use on menu items to look up the item title. Typing the first
-       * letter of an item when the menu is open focuses that item. If unset, `textContent`
-       * will be used.
-       *
-       * @attribute attrForItemTitle
-       * @type String
-       */
-      attrForItemTitle: {
-        type: String
-      }
-    },
-
-    hostAttributes: {
-      'role': 'menu',
-      'tabindex': '0'
-    },
-
-    observers: [
-      '_updateMultiselectable(multi)'
-    ],
-
-    listeners: {
-      'focus': '_onFocus',
-      'keydown': '_onKeydown'
-    },
-
-    keyBindings: {
-      'up': '_onUpKey',
-      'down': '_onDownKey',
-      'esc': '_onEscKey',
-      'enter': '_onEnterKey',
-      'shift+tab:keydown': '_onShiftTabDown'
-    },
-
-    _updateMultiselectable: function(multi) {
-      if (multi) {
-        this.setAttribute('aria-multiselectable', 'true');
-      } else {
-        this.removeAttribute('aria-multiselectable');
-      }
-    },
-
-    _onShiftTabDown: function() {
-      var oldTabIndex;
-
-      Polymer.IronMenuBehaviorImpl._shiftTabPressed = true;
-
-      oldTabIndex = this.getAttribute('tabindex');
-
-      this.setAttribute('tabindex', '-1');
-
-      this.async(function() {
-        this.setAttribute('tabindex', oldTabIndex);
-        Polymer.IronMenuBehaviorImpl._shiftTabPressed = false;
-      // Note: polymer/polymer#1305
-      }, 1);
-    },
-
-    _applySelection: function(item, isSelected) {
-      if (isSelected) {
-        item.setAttribute('aria-selected', 'true');
-      } else {
-        item.removeAttribute('aria-selected');
-      }
-
-      Polymer.IronSelectableBehavior._applySelection.apply(this, arguments);
-    },
-
-    _focusedItemChanged: function(focusedItem, old) {
-      old && old.setAttribute('tabindex', '-1');
-      if (focusedItem) {
-        focusedItem.setAttribute('tabindex', '0');
-        focusedItem.focus();
-      }
-    },
-
-    select: function(value) {
-      if (this._defaultFocusAsync) {
-        this.cancelAsync(this._defaultFocusAsync);
-        this._defaultFocusAsync = null;
-      }
-      var item = this._valueToItem(value);
-      this._setFocusedItem(item);
-      Polymer.IronMultiSelectableBehaviorImpl.select.apply(this, arguments);
-    },
-
-    _onFocus: function(event) {
-      if (Polymer.IronMenuBehaviorImpl._shiftTabPressed) {
-        return;
-      }
-      // do not focus the menu itself
-      this.blur();
-      // clear the cached focus item
-      this._setFocusedItem(null);
-      this._defaultFocusAsync = this.async(function() {
-        // focus the selected item when the menu receives focus, or the first item
-        // if no item is selected
-        var selectedItem = this.multi ? (this.selectedItems && this.selectedItems[0]) : this.selectedItem;
-        if (selectedItem) {
-          this._setFocusedItem(selectedItem);
-        } else {
-          this._setFocusedItem(this.items[0]);
-        }
-      // async 100ms to wait for `select` to get called from `_itemActivate`
-      }, 100);
-    },
-
-    _onUpKey: function() {
-      // up and down arrows moves the focus
-      this._focusPrevious();
-    },
-
-    _onDownKey: function() {
-      this._focusNext();
-    },
-
-    _onEscKey: function() {
-      // esc blurs the control
-      this.focusedItem.blur();
-    },
-
-    _onEnterKey: function(event) {
-      // enter activates the item unless it is disabled
-      this._activateFocused(event.detail.keyboardEvent);
-    },
-
-    _onKeydown: function(event) {
-      if (this.keyboardEventMatchesKeys(event, 'up down esc enter')) {
-        return;
-      }
-
-      // all other keys focus the menu item starting with that character
-      this._focusWithKeyboardEvent(event);
-    },
-
-    _focusWithKeyboardEvent: function(event) {
-      for (var i = 0, item; item = this.items[i]; i++) {
-        var attr = this.attrForItemTitle || 'textContent';
-        var title = item[attr] || item.getAttribute(attr);
-        if (title && title.trim().charAt(0).toLowerCase() === String.fromCharCode(event.keyCode).toLowerCase()) {
-          this._setFocusedItem(item);
-          break;
-        }
-      }
-    },
-
-    _activateFocused: function(event) {
-      if (!this.focusedItem.hasAttribute('disabled')) {
-        this._activateHandler(event);
-      }
-    },
-
-    _focusPrevious: function() {
-      var length = this.items.length;
-      var index = (Number(this.indexOf(this.focusedItem)) - 1 + length) % length;
-      this._setFocusedItem(this.items[index]);
-    },
-
-    _focusNext: function() {
-      var index = (Number(this.indexOf(this.focusedItem)) + 1) % this.items.length;
-      this._setFocusedItem(this.items[index]);
-    }
-
-  };
-
-  Polymer.IronMenuBehaviorImpl._shiftTabPressed = false;
-
-  /** @polymerBehavior Polymer.IronMenuBehavior */
-  Polymer.IronMenuBehavior = [
-    Polymer.IronMultiSelectableBehavior,
-    Polymer.IronA11yKeysBehavior,
-    Polymer.IronMenuBehaviorImpl
-  ];
-
-</script>