ChromeOS OOBE: More accessibility fixes.

chrome/browser/resources/chromeos/login/oobe_a11y_option.js

Index: chrome/browser/resources/chromeos/login/oobe_a11y_option.js
diff --git a/chrome/browser/resources/chromeos/login/oobe_a11y_option.js b/chrome/browser/resources/chromeos/login/oobe_a11y_option.js
index b053ec7435baca2974db9f69273466a8d878434e..2596b63e400a880a12c6e8805e4e3bae81c4518d 100644
--- a/chrome/browser/resources/chromeos/login/oobe_a11y_option.js
+++ b/chrome/browser/resources/chromeos/login/oobe_a11y_option.js
@@ -22,6 +22,10 @@ Polymer({
 
     /**
      * ARIA-label for the button.
+     *
+     * Note that we are not using "aria-label" property here, because
+     * we want to pass the label value but not actually declare it as an
+     * ARIA property anywhere but the actual target element.
      */
     labelForAria: String,
   },