WebUI: Add cr-policy-pref-indicator tests

ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js

Index: ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js
diff --git a/ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js b/ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js
index 205465c71d740befa43794ae8a3c50975c69e8e6..63639392b7cec6c059630101f4aceb7a2d20ad3f 100644
--- a/ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js
+++ b/ui/webui/resources/cr_elements/policy/cr_policy_indicator_behavior.js
@@ -48,11 +48,12 @@ var CrPolicyIndicatorBehavior = {
    * @private
    */
   getPolicyIndicatorIcon: function(type) {
-    var icon = '';
+    var icon;
     switch (type) {
       case CrPolicyIndicatorType.EXTENSION:
       case CrPolicyIndicatorType.NONE:
-        return icon;
+        icon = 'domain';  // Set a valid icon for accessibility audit

[michaelpg, 2017/02/15 02:02:11]

why does the accessibility audit care if the element is hidden (which it should
be in this case, I thought)?

seems like having a real icon here could contribute to bugs (or accidentally
correct behavior) in the future

[stevenjb, 2017/02/15 02:23:29]

Turns out we don't need this any more, so nevermind.

+        break;
       case CrPolicyIndicatorType.PRIMARY_USER:
         icon = 'cr:group';
         break;
@@ -66,12 +67,13 @@ var CrPolicyIndicatorBehavior = {
         break;
       default:
         assertNotReached();
+        icon = '';  // For closure
     }
     return icon;
   },
 
   /**
-   * @param {CrPolicyIndicatorType} type
+   * @param {!CrPolicyIndicatorType} type
    * @param {string} name The name associated with the indicator. See
    *     chrome.settingsPrivate.PrefObject.controlledByName
    * @param {boolean=} opt_matches For RECOMMENDED only, whether the indicator