Remove third_party/polymer from .gitignore

third_party/polymer/v1_0/components/paper-dialog-behavior/paper-dialog-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-overlay-behavior/iron-overlay-behavior.html">
-<link rel="import" href="../paper-styles/paper-styles.html">
-
-<script>
-
-/**
-Use `Polymer.PaperDialogBehavior` and `paper-dialog-common.css` to implement a Material Design
-dialog.
-
-For example, if `<paper-dialog-impl>` implements this behavior:
-
-    <paper-dialog-impl>
-        <h2>Header</h2>
-        <div>Dialog body</div>
-        <div class="buttons">
-            <paper-button dialog-dismiss>Cancel</paper-button>
-            <paper-button dialog-confirm>Accept</paper-button>
-        </div>
-    </paper-dialog-impl>
-
-`paper-dialog-common.css` provide styles for a header, content area, and an action area for buttons.
-Use the `<h2>` tag for the header and the `buttons` class for the action area. You can use the
-`paper-dialog-scrollable` element (in its own repository) if you need a scrolling content area.
-
-Use the `dialog-dismiss` and `dialog-confirm` attributes on interactive controls to close the
-dialog. If the user dismisses the dialog with `dialog-confirm`, the `closingReason` will update
-to include `confirmed: true`.
-
-### Styling
-
-The following custom properties and mixins are available for styling.
-
-Custom property | Description | Default
-----------------|-------------|----------
-`--paper-dialog-background-color` | Dialog background color                     | `--primary-background-color`
-`--paper-dialog-color`            | Dialog foreground color                     | `--primary-text-color`
-`--paper-dialog`                  | Mixin applied to the dialog                 | `{}`
-`--paper-dialog-title`            | Mixin applied to the title (`<h2>`) element | `{}`
-`--paper-dialog-button-color`     | Button area foreground color                | `--default-primary-color`
-
-### Accessibility
-
-This element has `role="dialog"` by default. Depending on the context, it may be more appropriate
-to override this attribute with `role="alertdialog"`.
-
-If `modal` is set, the element will set `aria-modal` and prevent the focus from exiting the element.
-It will also ensure that focus remains in the dialog.
-
-The `aria-labelledby` attribute will be set to the header element, if one exists.
-
-@hero hero.svg
-@demo demo/index.html
-@polymerBehavior Polymer.PaperDialogBehavior
-*/
-
-  Polymer.PaperDialogBehaviorImpl = {
-
-    hostAttributes: {
-      'role': 'dialog',
-      'tabindex': '-1'
-    },
-
-    properties: {
-
-      /**
-       * If `modal` is true, this implies `no-cancel-on-outside-click` and `with-backdrop`.
-       */
-      modal: {
-        observer: '_modalChanged',
-        type: Boolean,
-        value: false
-      },
-
-      /** @type {?Node} */
-      _lastFocusedElement: {
-        type: Object
-      },
-
-      _boundOnFocus: {
-        type: Function,
-        value: function() {
-          return this._onFocus.bind(this);
-        }
-      },
-
-      _boundOnBackdropClick: {
-        type: Function,
-        value: function() {
-          return this._onBackdropClick.bind(this);
-        }
-      }
-
-    },
-
-    listeners: {
-      'click': '_onDialogClick',
-      'iron-overlay-opened': '_onIronOverlayOpened',
-      'iron-overlay-closed': '_onIronOverlayClosed'
-    },
-
-    attached: function() {
-      this._observer = this._observe(this);
-      this._updateAriaLabelledBy();
-    },
-
-    detached: function() {
-      if (this._observer) {
-        this._observer.disconnect();
-      }
-    },
-
-    _observe: function(node) {
-      var observer = new MutationObserver(function() {
-        this._updateAriaLabelledBy();
-      }.bind(this));
-      observer.observe(node, {
-        childList: true,
-        subtree: true
-      });
-      return observer;
-    },
-
-    _modalChanged: function() {
-      if (this.modal) {
-        this.setAttribute('aria-modal', 'true');
-      } else {
-        this.setAttribute('aria-modal', 'false');
-      }
-      // modal implies noCancelOnOutsideClick and withBackdrop if true, don't overwrite
-      // those properties otherwise.
-      if (this.modal) {
-        this.noCancelOnOutsideClick = true;
-        this.withBackdrop = true;
-      }
-    },
-
-    _updateAriaLabelledBy: function() {
-      var header = Polymer.dom(this).querySelector('h2');
-      if (!header) {
-        this.removeAttribute('aria-labelledby');
-        return;
-      }
-      var headerId = header.getAttribute('id');
-      if (headerId && this.getAttribute('aria-labelledby') === headerId) {
-        return;
-      }
-      // set aria-describedBy to the header element
-      var labelledById;
-      if (headerId) {
-        labelledById = headerId;
-      } else {
-        labelledById = 'paper-dialog-header-' + new Date().getUTCMilliseconds();
-        header.setAttribute('id', labelledById);
-      }
-      this.setAttribute('aria-labelledby', labelledById);
-    },
-
-    _updateClosingReasonConfirmed: function(confirmed) {
-      this.closingReason = this.closingReason || {};
-      this.closingReason.confirmed = confirmed;
-    },
-
-    _onDialogClick: function(event) {
-      var target = event.target;
-      while (target && target !== this) {
-        if (target.hasAttribute) {
-          if (target.hasAttribute('dialog-dismiss')) {
-            this._updateClosingReasonConfirmed(false);
-            this.close();
-            break;
-          } else if (target.hasAttribute('dialog-confirm')) {
-            this._updateClosingReasonConfirmed(true);
-            this.close();
-            break;
-          }
-        }
-        target = target.parentNode;
-      }
-    },
-
-    _onIronOverlayOpened: function() {
-      if (this.modal) {
-        document.body.addEventListener('focus', this._boundOnFocus, true);
-        this.backdropElement.addEventListener('click', this._boundOnBackdropClick);
-      }
-    },
-
-    _onIronOverlayClosed: function() {
-      document.body.removeEventListener('focus', this._boundOnFocus, true);
-      this.backdropElement.removeEventListener('click', this._boundOnBackdropClick);
-    },
-
-    _onFocus: function(event) {
-      if (this.modal) {
-        var target = event.target;
-        while (target && target !== this && target !== document.body) {
-          target = target.parentNode;
-        }
-        if (target) {
-          if (target === document.body) {
-            if (this._lastFocusedElement) {
-              this._lastFocusedElement.focus();
-            } else {
-              this._focusNode.focus();
-            }
-          } else {
-            this._lastFocusedElement = event.target;
-          }
-        }
-      }
-    },
-
-    _onBackdropClick: function() {
-      if (this.modal) {
-        if (this._lastFocusedElement) {
-          this._lastFocusedElement.focus();
-        } else {
-          this._focusNode.focus();
-        }
-      }
-    }
-
-  };
-
-  /** @polymerBehavior */
-  Polymer.PaperDialogBehavior = [Polymer.IronOverlayBehavior, Polymer.PaperDialogBehaviorImpl];
-
-</script>