diff --git a/core/components/menu/menu.js b/core/components/menu/menu.js
index 00fd13e4e..4386f47ac 100644
--- a/core/components/menu/menu.js
+++ b/core/components/menu/menu.js
@@ -92,7 +92,7 @@ Blockly.Menu.prototype.blur = function() {
 
 /**
  * Set the menu accessibility role.
- * @param {!Blockly.utils.aria.Role|string} roleName role name.
+ * @param {!Blockly.utils.aria.Role} roleName role name.
  * @package
  */
 Blockly.Menu.prototype.setRole = function(roleName) {
diff --git a/core/components/menu/menuitem.js b/core/components/menu/menuitem.js
index 7e529279d..9639aab43 100644
--- a/core/components/menu/menuitem.js
+++ b/core/components/menu/menuitem.js
@@ -95,8 +95,8 @@ Blockly.MenuItem.prototype.createDom = function() {
   Blockly.utils.aria.setRole(element, this.roleName_ || (this.checkable_ ?
       Blockly.utils.aria.Role.MENUITEMCHECKBOX :
       Blockly.utils.aria.Role.MENUITEM));
-  Blockly.utils.aria.setState(element,
-      Blockly.utils.aria.State.SELECTED, (this.checkable_ && this.checked_) || false);
+  Blockly.utils.aria.setState(element, Blockly.utils.aria.State.SELECTED,
+      (this.checkable_ && this.checked_) || false);
 };
 
 /**
@@ -164,7 +164,7 @@ Blockly.MenuItem.prototype.getValue = function() {
 
 /**
  * Set the menu accessibility role.
- * @param {!Blockly.utils.aria.Role|string} roleName role name.
+ * @param {!Blockly.utils.aria.Role} roleName Role name.
  * @package
  */
 Blockly.MenuItem.prototype.setRole = function(roleName) {
diff --git a/core/components/tree/basenode.js b/core/components/tree/basenode.js
index 9127dbe32..40130fb71 100644
--- a/core/components/tree/basenode.js
+++ b/core/components/tree/basenode.js
@@ -188,10 +188,8 @@ Blockly.tree.BaseNode.prototype.initAccessibility = function() {
       label.id = this.getId() + '.label';
     }
 
-    Blockly.utils.aria.setRole(el,
-        Blockly.utils.aria.Role.TREEITEM);
-    Blockly.utils.aria.setState(el,
-        Blockly.utils.aria.State.SELECTED, false);
+    Blockly.utils.aria.setRole(el, Blockly.utils.aria.Role.TREEITEM);
+    Blockly.utils.aria.setState(el, Blockly.utils.aria.State.SELECTED, false);
     Blockly.utils.aria.setState(el,
         Blockly.utils.aria.State.LEVEL, this.getDepth());
     if (label) {
diff --git a/core/field_colour.js b/core/field_colour.js
index 2e6913a68..6878977e6 100644
--- a/core/field_colour.js
+++ b/core/field_colour.js
@@ -557,13 +557,12 @@ Blockly.FieldColour.prototype.dropdownCreate_ = function() {
   table.className = 'blocklyColourTable';
   table.tabIndex = 0;
   table.dir = 'ltr';
-  Blockly.utils.aria.setRole(table,
-      Blockly.utils.aria.Role.GRID);
-  Blockly.utils.aria.setState(table,
-      Blockly.utils.aria.State.EXPANDED, true);
-  Blockly.utils.aria.setState(table, 'rowcount',
+  Blockly.utils.aria.setRole(table, Blockly.utils.aria.Role.GRID);
+  Blockly.utils.aria.setState(table, Blockly.utils.aria.State.EXPANDED, true);
+  Blockly.utils.aria.setState(table, Blockly.utils.aria.State.ROWCOUNT,
       Math.floor(colours.length / columns));
-  Blockly.utils.aria.setState(table, 'colcount', columns);
+  Blockly.utils.aria.setState(table, Blockly.utils.aria.State.COLCOUNT,
+      columns);
   var row;
   for (var i = 0; i < colours.length; i++) {
     if (i % columns == 0) {
diff --git a/core/field_dropdown.js b/core/field_dropdown.js
index d01a89c1a..3f38b3a6d 100644
--- a/core/field_dropdown.js
+++ b/core/field_dropdown.js
@@ -33,6 +33,7 @@ goog.require('Blockly.Menu');
 goog.require('Blockly.MenuItem');
 goog.require('Blockly.navigation');
 goog.require('Blockly.utils');
+goog.require('Blockly.utils.aria');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.object');
 goog.require('Blockly.utils.Size');
@@ -251,7 +252,7 @@ Blockly.FieldDropdown.prototype.showEditor_ = function() {
 Blockly.FieldDropdown.prototype.dropdownCreate_ = function() {
   var menu = new Blockly.Menu();
   menu.setRightToLeft(this.sourceBlock_.RTL);
-  menu.setRole('listbox');
+  menu.setRole(Blockly.utils.aria.Role.LISTBOX);
 
   var options = this.getOptions(false);
   this.selectedMenuItem_ = null;
@@ -266,7 +267,7 @@ Blockly.FieldDropdown.prototype.dropdownCreate_ = function() {
       content = image;
     }
     var menuItem = new Blockly.MenuItem(content);
-    menuItem.setRole('option');
+    menuItem.setRole(Blockly.utils.aria.Role.OPTION);
     menuItem.setRightToLeft(this.sourceBlock_.RTL);
     menuItem.setValue(value);
     menuItem.setCheckable(true);
diff --git a/core/field_multilineinput.js b/core/field_multilineinput.js
index 349afc37e..41e16b0fd 100644
--- a/core/field_multilineinput.js
+++ b/core/field_multilineinput.js
@@ -29,6 +29,7 @@ goog.require('Blockly.Css');
 goog.require('Blockly.DropDownDiv');
 goog.require('Blockly.FieldTextInput');
 goog.require('Blockly.utils');
+goog.require('Blockly.utils.aria');
 goog.require('Blockly.utils.Coordinate');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.KeyCodes');
@@ -178,10 +179,12 @@ Blockly.FieldMultilineInput.prototype.render_ = function() {
     var htmlInput = /** @type {!HTMLElement} */(this.htmlInput_);
     if (!this.isTextValid_) {
       Blockly.utils.dom.addClass(htmlInput, 'blocklyInvalidInput');
-      Blockly.utils.aria.setState(htmlInput, 'invalid', true);
+      Blockly.utils.aria.setState(htmlInput,
+          Blockly.utils.aria.State.INVALID, true);
     } else {
       Blockly.utils.dom.removeClass(htmlInput, 'blocklyInvalidInput');
-      Blockly.utils.aria.setState(htmlInput, 'invalid', false);
+      Blockly.utils.aria.setState(htmlInput,
+          Blockly.utils.aria.State.INVALID, false);
     }
   }
 };
diff --git a/core/field_number.js b/core/field_number.js
index be5ac735d..9cdd99439 100644
--- a/core/field_number.js
+++ b/core/field_number.js
@@ -25,6 +25,7 @@ goog.provide('Blockly.FieldNumber');
 
 goog.require('Blockly.fieldRegistry');
 goog.require('Blockly.FieldTextInput');
+goog.require('Blockly.utils.aria');
 goog.require('Blockly.utils.object');
 
 
diff --git a/core/field_textinput.js b/core/field_textinput.js
index f6ebb0a22..2d7d3b762 100644
--- a/core/field_textinput.js
+++ b/core/field_textinput.js
@@ -77,7 +77,7 @@ Blockly.FieldTextInput = function(opt_value, opt_validator, opt_config) {
    * @private
    */
   this.onKeyDownWrapper_ = null;
-  
+
   /**
    * Key input event data.
    * @type {?Blockly.EventData}
@@ -206,10 +206,12 @@ Blockly.FieldTextInput.prototype.render_ = function() {
     var htmlInput = /** @type {!HTMLElement} */(this.htmlInput_);
     if (!this.isTextValid_) {
       Blockly.utils.dom.addClass(htmlInput, 'blocklyInvalidInput');
-      Blockly.utils.aria.setState(htmlInput, 'invalid', true);
+      Blockly.utils.aria.setState(htmlInput,
+          Blockly.utils.aria.State.INVALID, true);
     } else {
       Blockly.utils.dom.removeClass(htmlInput, 'blocklyInvalidInput');
-      Blockly.utils.aria.setState(htmlInput, 'invalid', false);
+      Blockly.utils.aria.setState(htmlInput,
+          Blockly.utils.aria.State.INVALID, false);
     }
   }
 };
diff --git a/core/utils/aria.js b/core/utils/aria.js
index 14f31beb2..3ba1eac11 100644
--- a/core/utils/aria.js
+++ b/core/utils/aria.js
@@ -44,55 +44,6 @@ Blockly.utils.aria.ROLE_ATTRIBUTE_ = 'role';
  * @enum {string}
  */
 Blockly.utils.aria.Role = {
-  // ARIA role for an alert element that doesn't need to be explicitly closed.
-  ALERT: 'alert',
-
-  // ARIA role for an alert dialog element that takes focus and must be closed.
-  ALERTDIALOG: 'alertdialog',
-
-  // ARIA role for an application that implements its own keyboard navigation.
-  APPLICATION: 'application',
-
-  // ARIA role for an article.
-  ARTICLE: 'article',
-
-  // ARIA role for a banner containing mostly site content, not page content.
-  BANNER: 'banner',
-
-  // ARIA role for a button element.
-  BUTTON: 'button',
-
-  // ARIA role for a checkbox button element; use with the CHECKED state.
-  CHECKBOX: 'checkbox',
-
-  // ARIA role for a column header of a table or grid.
-  COLUMNHEADER: 'columnheader',
-
-  // ARIA role for a combo box element.
-  COMBOBOX: 'combobox',
-
-  // ARIA role for a supporting section of the document.
-  COMPLEMENTARY: 'complementary',
-
-  // ARIA role for a large perceivable region that contains information
-  // about the parent document.
-  CONTENTINFO: 'contentinfo',
-
-  // ARIA role for a definition of a term or concept.
-  DEFINITION: 'definition',
-
-  // ARIA role for a dialog, some descendant must take initial focus.
-  DIALOG: 'dialog',
-
-  // ARIA role for a directory, like a table of contents.
-  DIRECTORY: 'directory',
-
-  // ARIA role for a part of a page that's a document, not a web application.
-  DOCUMENT: 'document',
-
-  // ARIA role for a landmark region logically considered one form.
-  FORM: 'form',
-
   // ARIA role for an interactive control of tabular data.
   GRID: 'grid',
 
@@ -102,57 +53,18 @@ Blockly.utils.aria.Role = {
   // ARIA role for a group of related elements like tree item siblings.
   GROUP: 'group',
 
-  // ARIA role for a heading element.
-  HEADING: 'heading',
-
-  // ARIA role for a container of elements that together comprise one image.
-  IMG: 'img',
-
-  // ARIA role for a link.
-  LINK: 'link',
-
-  // ARIA role for a list of non-interactive list items.
-  LIST: 'list',
-
   // ARIA role for a listbox.
   LISTBOX: 'listbox',
 
-  // ARIA role for a list item.
-  LISTITEM: 'listitem',
-
-  // ARIA role for a live region where new information is added.
-  LOG: 'log',
-
-  // ARIA landmark role for the main content in a document. Use only once.
-  MAIN: 'main',
-
-  // ARIA role for a live region of non-essential information that changes.
-  MARQUEE: 'marquee',
-
-  // ARIA role for a mathematical expression.
-  MATH: 'math',
-
   // ARIA role for a popup menu.
   MENU: 'menu',
 
-  // ARIA role for a menubar element containing menu elements.
-  MENUBAR: 'menubar',
-
   // ARIA role for menu item elements.
   MENUITEM: 'menuitem',
 
   // ARIA role for a checkbox box element inside a menu.
   MENUITEMCHECKBOX: 'menuitemcheckbox',
 
-  // ARIA role for a radio button element inside a menu.
-  MENUITEMRADIO: 'menuitemradio',
-
-  // ARIA landmark role for a collection of navigation links.
-  NAVIGATION: 'navigation',
-
-  // ARIA role for a section ancillary to the main content.
-  NOTE: 'note',
-
   // ARIA role for option items that are  children of combobox, listbox, menu,
   // radiogroup, or tree elements.
   OPTION: 'option',
@@ -160,78 +72,12 @@ Blockly.utils.aria.Role = {
   // ARIA role for ignorable cosmetic elements with no semantic significance.
   PRESENTATION: 'presentation',
 
-  // ARIA role for a progress bar element.
-  PROGRESSBAR: 'progressbar',
-
-  // ARIA role for a radio button element.
-  RADIO: 'radio',
-
-  // ARIA role for a group of connected radio button elements.
-  RADIOGROUP: 'radiogroup',
-
-  // ARIA role for an important region of the page.
-  REGION: 'region',
-
   // ARIA role for a row of cells in a grid.
   ROW: 'row',
 
-  // ARIA role for a group of one or more rows in a grid.
-  ROWGROUP: 'rowgroup',
-
-  // ARIA role for a row header of a table or grid.
-  ROWHEADER: 'rowheader',
-
-  // ARIA role for a scrollbar element.
-  SCROLLBAR: 'scrollbar',
-
-  // ARIA landmark role for a part of the page providing search functionality.
-  SEARCH: 'search',
-
-  // ARIA role for a menu separator.
-  SEPARATOR: 'separator',
-
-  // ARIA role for a slider.
-  SLIDER: 'slider',
-
-  // ARIA role for a spin button.
-  SPINBUTTON: 'spinbutton',
-
-  // ARIA role for a live region with advisory info less severe than an alert.
-  STATUS: 'status',
-
-  // ARIA role for a tab button.
-  TAB: 'tab',
-
-  // ARIA role for a table.
-  TABLE: 'table',
-
-  // ARIA role for a tab bar (i.e. a list of tab buttons).
-  TABLIST: 'tablist',
-
-  // ARIA role for a tab page (i.e. the element holding tab contents).
-  TABPANEL: 'tabpanel',
-
-  // ARIA role for a textbox element.
-  TEXTBOX: 'textbox',
-
-  // ARIA role for a textinfo element.
-  TEXTINFO: 'textinfo',
-
-  // ARIA role for an element displaying elapsed time or time remaining.
-  TIMER: 'timer',
-
-  // ARIA role for a toolbar element.
-  TOOLBAR: 'toolbar',
-
-  // ARIA role for a tooltip element.
-  TOOLTIP: 'tooltip',
-
   // ARIA role for a tree.
   TREE: 'tree',
 
-  // ARIA role for a grid whose rows can be expanded and collapsed like a tree.
-  TREEGRID: 'treegrid',
-
   // ARIA role for a tree item that sometimes may be expanded or collapsed.
   TREEITEM: 'treeitem'
 };
@@ -246,65 +92,15 @@ Blockly.utils.aria.State = {
   // for example the selected item in a list box. Value: ID of an element.
   ACTIVEDESCENDANT: 'activedescendant',
 
-  // ARIA property that, if true, indicates that all of a changed region should
-  // be presented, instead of only parts. Value: one of {true, false}.
-  ATOMIC: 'atomic',
-
-  // ARIA property to specify that input completion is provided. Value:
-  // one of {'inline', 'list', 'both', 'none'}.
-  AUTOCOMPLETE: 'autocomplete',
-
-  // ARIA state to indicate that an element and its subtree are being updated.
-  // Value: one of {true, false}.
-  BUSY: 'busy',
-
-  // ARIA state for a checked item. Value: one of {'true', 'false', 'mixed',
-  // undefined}.
-  CHECKED: 'checked',
-
-  // ARIA state that defines an element's column index or position with respect
-  // to the total number of columns within a table, grid, or treegrid.
-  // Value: number.
-  COLINDEX: 'colindex',
-
-  // ARIA property that identifies the element or elements whose contents or
-  // presence are controlled by this element.
-  // Value: space-separated IDs of other elements.
-  CONTROLS: 'controls',
-
-  // ARIA property that identifies the element or elements that describe
-  // this element. Value: space-separated IDs of other elements.
-  DESCRIBEDBY: 'describedby',
-
-  // ARIA state for a disabled item. Value: one of {true, false}.
-  DISABLED: 'disabled',
-
-  // ARIA property that indicates what functions can be performed when a
-  // dragged object is released on the drop target.  Value: one of
-  // {'copy', 'move', 'link', 'execute', 'popup', 'none'}.
-  DROPEFFECT: 'dropeffect',
+  // ARIA property defines the total number of columns in a table, grid, or
+  // treegrid.
+  // Value: integer.
+  COLCOUNT: 'colcount',
 
   // ARIA state for setting whether the element like a tree node is expanded.
   // Value: one of {true, false, undefined}.
   EXPANDED: 'expanded',
 
-  // ARIA property that identifies the next element (or elements) in the
-  // recommended reading order of content. Value: space-separated ids of
-  // elements to flow to.
-  FLOWTO: 'flowto',
-
-  // ARIA state that indicates an element's "grabbed" state in drag-and-drop.
-  // Value: one of {true, false, undefined}.
-  GRABBED: 'grabbed',
-
-  // ARIA property indicating whether the element has a popup.
-  // Value: one of {true, false}.
-  HASPOPUP: 'haspopup',
-
-  // ARIA state indicating that the element is not visible or perceivable
-  // to any user. Value: one of {true, false}.
-  HIDDEN: 'hidden',
-
   // ARIA state indicating that the entered value does not conform. Value:
   // one of {false, true, 'grammar', 'spelling'}
   INVALID: 'invalid',
@@ -321,54 +117,18 @@ Blockly.utils.aria.State = {
   // Value: integer.
   LEVEL: 'level',
 
-  // ARIA property indicating that an element will be updated, and
-  // describes the types of updates the user agents, assistive technologies,
-  // and user can expect from the live region. Value: one of {'off', 'polite',
-  // 'assertive'}.
-  LIVE: 'live',
-
-  // ARIA property indicating whether a text box can accept multiline input.
-  // Value: one of {true, false}.
-  MULTILINE: 'multiline',
-
-  // ARIA property indicating if the user may select more than one item.
-  // Value: one of {true, false}.
-  MULTISELECTABLE: 'multiselectable',
-
   // ARIA property indicating if the element is horizontal or vertical.
   // Value: one of {'vertical', 'horizontal'}.
   ORIENTATION: 'orientation',
 
-  // ARIA property creating a visual, functional, or contextual parent/child
-  // relationship when the DOM hierarchy can't be used to represent it.
-  // Value: Space-separated IDs of elements.
-  OWNS: 'owns',
-
   // ARIA property that defines an element's number of position in a list.
   // Value: integer.
   POSINSET: 'posinset',
 
-  // ARIA state for a pressed item.
-  // Value: one of {true, false, undefined, 'mixed'}.
-  PRESSED: 'pressed',
-
-  // ARIA property indicating that an element is not editable.
-  // Value: one of {true, false}.
-  READONLY: 'readonly',
-
-  // ARIA property indicating that change notifications within this subtree
-  // of a live region should be announced. Value: one of {'additions',
-  // 'removals', 'text', 'all', 'additions text'}.
-  RELEVANT: 'relevant',
-
-  // ARIA property indicating that user input is required on this element
-  // before a form may be submitted. Value: one of {true, false}.
-  REQUIRED: 'required',
-
-  // ARIA state that defines an element's row index or position with respect
-  // to the total number of rows within a table, grid, or treegrid.
-  // Value: number.
-  ROWINDEX: 'rowindex',
+  // ARIA property defines the total number of rows in a table, grid, or
+  // treegrid.
+  // Value: integer.
+  ROWCOUNT: 'rowcount',
 
   // ARIA state for setting the currently selected item in the list.
   // Value: one of {true, false, undefined}.
@@ -377,72 +137,30 @@ Blockly.utils.aria.State = {
   // ARIA property defining the number of items in a list. Value: integer.
   SETSIZE: 'setsize',
 
-  // ARIA property indicating if items are sorted. Value: one of {'ascending',
-  // 'descending', 'none', 'other'}.
-  SORT: 'sort',
-
   // ARIA property for slider maximum value. Value: number.
   VALUEMAX: 'valuemax',
 
   // ARIA property for slider minimum value. Value: number.
-  VALUEMIN: 'valuemin',
-
-  // ARIA property for slider active value. Value: number.
-  VALUENOW: 'valuenow',
-
-  // ARIA property for slider active value represented as text.
-  // Value: string.
-  VALUETEXT: 'valuetext'
+  VALUEMIN: 'valuemin'
 };
 
 /**
- * Sets the role of an element. If the roleName is
- * empty string or null, the role for the element is removed.
- * We encourage clients to call the goog.a11y.aria.removeRole
- * method instead of setting null and empty string values.
- * Special handling for this case is added to ensure
- * backword compatibility with existing code.
+ * Sets the role of an element.
  *
  * Similar to Closure's goog.a11y.aria
  *
  * @param {!Element} element DOM node to set role of.
- * @param {!Blockly.utils.aria.Role|string} roleName role name(s).
+ * @param {!Blockly.utils.aria.Role} roleName Role name.
  */
 Blockly.utils.aria.setRole = function(element, roleName) {
-  if (!roleName) {
-    // Setting the ARIA role to empty string is not allowed
-    // by the ARIA standard.
-    Blockly.utils.aria.removeRole(element);
-  } else {
-    element.setAttribute(Blockly.utils.aria.ROLE_ATTRIBUTE_, roleName);
-  }
-};
-
-/**
- * Gets role of an element.
- * Copied from Closure's goog.a11y.aria
- * @param {!Element} element DOM element to get role of.
- * @return {?Blockly.utils.aria.Role} ARIA Role name.
- */
-Blockly.utils.aria.getRole = function(element) {
-  var role = element.getAttribute(Blockly.utils.aria.ROLE_ATTRIBUTE_);
-  return /** @type {Blockly.utils.aria.Role} */ (role) || null;
-};
-
-/**
- * Removes role of an element.
- * Copied from Closure's goog.a11y.aria
- * @param {!Element} element DOM element to remove the role from.
- */
-Blockly.utils.aria.removeRole = function(element) {
-  element.removeAttribute(Blockly.utils.aria.ROLE_ATTRIBUTE_);
+  element.setAttribute(Blockly.utils.aria.ROLE_ATTRIBUTE_, roleName);
 };
 
 /**
  * Sets the state or property of an element.
  * Copied from Closure's goog.a11y.aria
  * @param {!Element} element DOM node where we set state.
- * @param {!(Blockly.utils.aria.State|string)} stateName State attribute being set.
+ * @param {!Blockly.utils.aria.State} stateName State attribute being set.
  *     Automatically adds prefix 'aria-' to the state name if the attribute is
  *     not an extra attribute.
  * @param {string|boolean|number|!Array.<string>} value Value
@@ -452,18 +170,6 @@ Blockly.utils.aria.setState = function(element, stateName, value) {
   if (Array.isArray(value)) {
     value = value.join(' ');
   }
-  var attrStateName = Blockly.utils.aria.getAriaAttributeName_(stateName);
+  var attrStateName = Blockly.utils.aria.ARIA_PREFIX_ + stateName;
   element.setAttribute(attrStateName, value);
 };
-
-/**
- * Adds the 'aria-' prefix to ariaName.
- * Copied from Closure's goog.a11y.aria
- * @param {string} ariaName ARIA state/property name.
- * @private
- * @return {string} The ARIA attribute name with added 'aria-' prefix.
- * @throws {Error} If no such attribute exists.
- */
-Blockly.utils.aria.getAriaAttributeName_ = function(ariaName) {
-  return Blockly.utils.aria.ARIA_PREFIX_ + ariaName;
-};