Moved functionallity of aria label to the iron-autogrow-textarea element.

Author: kalaspuffar

paper-textarea.html

@@ -56,6 +56,7 @@
       <iron-autogrow-textarea id="input" class="paper-input-input"
         bind-value="{{value}}"
         invalid="{{invalid}}"
+        label$="[[label]]"
         disabled$="[[disabled]]"
         autocomplete$="[[autocomplete]]"
         autofocus$="[[autofocus]]"
@@ -93,16 +94,6 @@
     ],
 
     properties: {
-      _ariaLabelledBy: {
-        observer: '_ariaLabelledByChanged',
-        type: String
-      },
-
-      _ariaDescribedBy: {
-        observer: '_ariaDescribedByChanged',
-        type: String
-      },
-
       /**
        * The initial number of rows.
        *
@@ -129,14 +120,6 @@
       }
     },
 
-    _ariaLabelledByChanged: function(ariaLabelledBy) {
-      this.$.input.textarea.setAttribute('aria-labelledby', ariaLabelledBy);
-    },
-
-    _ariaDescribedByChanged: function(ariaDescribedBy) {
-      this.$.input.textarea.setAttribute('aria-describedby', ariaDescribedBy);
-    },
-
     get _focusableElement() {
       return this.$.input.textarea;
     },