[SmartLock] a11y: Make radio buttons a single group for reader

The screen reader was reading each radio button three times.
Once for the polymer element and once for each inner div. To
Fix the issue I moved the aria attributes out the polymer
element and gave the inner divs the role of presentation so
they are not re-read.

Bug: 1007054
Change-Id: I9f4e8e2954a097c78bc1668e40b27fbff5759055
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1881480Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Commit-Queue: James Vecore <vecore@google.com>
Cr-Commit-Position: refs/heads/master@{#710509}

chrome/browser/resources/settings/multidevice_page/multidevice_radio_button.html

@@ -31,19 +31,16 @@
     </style>
 
     <div
-        aria-checked$="[[getAriaChecked_(checked)]]"
-        aria-disabled$="[[getAriaDisabled_(disabled)]]"
-        aria-labelledby="labelWrapper"
+        role="presentation"
         class="disc-wrapper"
         id="button"
-        role="radio"
         tabindex="0"
         on-keydown="onInputKeydown_">
       <div class="disc-border"></div>
       <div class="disc"></div>
     </div>
 
-    <div id="labelWrapper">
+    <div id="labelWrapper" role="presentation">
       <span>[[label]]</span>
     </div>
 

chrome/browser/resources/settings/multidevice_page/multidevice_radio_button.js

@@ -9,6 +9,34 @@ Polymer({
     CrRadioButtonBehavior,
   ],
 
+  hostAttributes: {'role': 'radio'},
+
+  properties: {
+    ariaChecked: {
+      type: String,
+      notify: true,
+      reflectToAttribute: true,
+      computed: 'getAriaChecked_(checked)'
+    },
+    ariaDisabled: {
+      type: String,
+      notify: true,
+      reflectToAttribute: true,
+      computed: 'getAriaDisabled_(disabled)'
+
+    },
+    ariaLabel: {
+      type: String,
+      notify: true,
+      reflectToAttribute: true,
+      computed: 'getLabel_(label)'
+    }
+  },
+
+  getLabel_: function(label) {
+    return label;
+  },
+
   /**
    * Prevents on-click handles on the control from being activated when the
    * indicator is clicked.