Bug 960248 - Fix range adjustments when on a label. r=yzen

accessible/src/jsat/content-script.js

@@ -343,13 +343,14 @@ function scroll(aMessage) {
 
 function adjustRange(aMessage) {
   function sendUpDownKey(aAccessible) {
-    let evt = content.document.createEvent('KeyboardEvent');
-    let keycode = aMessage.json.direction == 'forward' ?
-      content.KeyEvent.DOM_VK_DOWN : content.KeyEvent.DOM_VK_UP;
-    evt.initKeyEvent(
-      "keypress", false, true, null, false, false, false, false, keycode, 0);
-    if (aAccessible.DOMNode) {
-      aAccessible.DOMNode.dispatchEvent(evt);
+    let acc = Utils.getEmbeddedControl(aAccessible) || aAccessible;
+    if (acc.DOMNode) {
+      let evt = content.document.createEvent('KeyboardEvent');
+      let keycode = aMessage.json.direction == 'forward' ?
+        content.KeyEvent.DOM_VK_DOWN : content.KeyEvent.DOM_VK_UP;
+      evt.initKeyEvent(
+        "keypress", false, true, null, false, false, false, false, keycode, 0);
+      acc.DOMNode.dispatchEvent(evt);
     }
   }