Added aria label to element

iron-autogrow-textarea.html

@@ -104,7 +104,9 @@
 
     <!-- size the input/textarea with a div, because the textarea has intrinsic size in ff -->
     <div class="textarea-container fit">
+      <label id$="textarea-aria-label-[[_ariaLabelId]]">[[label]]</label>
       <textarea id="textarea"
+				aria-labelledby$="textarea-aria-label-[[_ariaLabelId]]"
         name$="[[name]]"
         autocomplete$="[[autocomplete]]"
         autofocus$="[[autofocus]]"
@@ -121,6 +123,8 @@
 </dom-module>
 
 <script>
+  Polymer.IronAutogrowHelper = {};
+  Polymer.IronAutogrowHelper.NextLabelID = 1;
 
   Polymer({
 
@@ -227,8 +231,22 @@
        */
       maxlength: {
         type: Number
-      }
+      },
 
+      /**
+       * Aria label to present to screen readers.
+       */
+      label: {
+        type: String
+      },
+
+      /**
+       * Aria label id used to get a unique id for element
+       */
+      _ariaLabelId: {
+        type: Number,
+        value: Polymer.IronAutogrowHelper.NextLabelID++
+      }
     },
 
     listeners: {

test/basic.html

@@ -50,6 +50,12 @@
       </template>
     </test-fixture>
 
+    <test-fixture id="label">
+      <template>
+        <iron-autogrow-textarea label="foo"></iron-autogrow-textarea>
+      </template>
+    </test-fixture>
+
     <script>
 
       suite('basic', function() {
@@ -184,6 +190,17 @@
         });
       });
 
+
+      suite('a11y', function() {
+
+        test('has aria-labelledby', function() {
+          var autogrow = fixture('label');
+
+          assert.isTrue(autogrow.textarea.hasAttribute('aria-labelledby'))
+          assert.equal(autogrow.textarea.getAttribute('aria-labelledby'), Polymer.dom(autogrow.root).querySelector('label').id, 'aria-labelledby points to the label');
+        });
+      });
+
     </script>
 
   </body>