Roll third_party/polymer.

third_party/polymer/v1_0/components-chromium/paper-dialog-behavior/paper-dialog-behavior-extracted.js

 /**
 Use `Polymer.PaperDialogBehavior` and `paper-dialog-shared-styles.html` 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">
@@ skipping 23 matching lines @@
 `--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'
@@ skipping 19 matching lines @@
       'tap': '_onDialogClick'
     },
 
     ready: function () {
       // Only now these properties can be read.
       this.__prevNoCancelOnOutsideClick = this.noCancelOnOutsideClick;
       this.__prevNoCancelOnEscKey = this.noCancelOnEscKey;
       this.__prevWithBackdrop = this.withBackdrop;
     },
 
-    attached: function() {
-      // this._observer is used by iron-overlay-behavior
-      this._ariaObserver = Polymer.dom(this).observeNodes(this._updateAriaLabelledBy);
-      this._updateAriaLabelledBy();
-    },
-
-    detached: function() {
-      Polymer.dom(this).unobserveNodes(this._ariaObserver);
-    },
-
     _modalChanged: function(modal, readied) {
       if (modal) {
         this.setAttribute('aria-modal', 'true');
       } else {
         this.setAttribute('aria-modal', 'false');
       }
 
       // modal implies noCancelOnOutsideClick, noCancelOnEscKey and withBackdrop.
       // We need to wait for the element to be ready before we can read the
       // properties values.
@@ skipping 11 matching lines @@
       } else {
         // If the value was changed to false, let it false.
         this.noCancelOnOutsideClick = this.noCancelOnOutsideClick &&
           this.__prevNoCancelOnOutsideClick;
         this.noCancelOnEscKey = this.noCancelOnEscKey &&
           this.__prevNoCancelOnEscKey;
         this.withBackdrop = this.withBackdrop && this.__prevWithBackdrop;
       }
     },
 
-    _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;
     },
 
     /**
      * Will dismiss the dialog if user clicked on an element with dialog-dismiss
      * or dialog-confirm attribute.
      */
     _onDialogClick: function(event) {
       // Search for the element with dialog-confirm or dialog-dismiss,
       // from the root target until this (excluded).
       var path = Polymer.dom(event).path;
       for (var i = 0; i < path.indexOf(this); i++) {
         var target = path[i];
         if (target.hasAttribute && (target.hasAttribute('dialog-dismiss') || target.hasAttribute('dialog-confirm'))) {
           this._updateClosingReasonConfirmed(target.hasAttribute('dialog-confirm'));
           this.close();
           event.stopPropagation();
           break;
         }
       }
     }
 
   };
 
   /** @polymerBehavior */
   Polymer.PaperDialogBehavior = [Polymer.IronOverlayBehavior, Polymer.PaperDialogBehaviorImpl];