Only process checked state changed for specific roles.

chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js

Index: chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js
diff --git a/chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js b/chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js
index 98391fcedd489c2a75cd0ac8b3aac829e4767a50..f054868b831967ccd7c8826b5d814b9260790741 100644
--- a/chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js
+++ b/chrome/browser/resources/chromeos/chromevox/cvox2/background/automation_predicate.js
@@ -289,4 +289,17 @@ AutomationPredicate.shouldIgnoreNode = function(node) {
        node.role == RoleType.staticText);
 };
 
+
+/**
+ * Returns if the node has a meaningful checked state.
+ * @param {!AutomationNode} node
+ * @return {boolean}
+ */
+AutomationPredicate.checkable = function(node) {
+  return node.role == RoleType.checkBox ||
+      node.role == RoleType.radioButton ||
+      node.role == RoleType.menuItemCheckBox ||
+      node.role == RoleType.menuItemRadio;
+};
+
 });  // goog.scope