[MD settings] show icon when content settings are controlled by an extension

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 fb6eb7cb3f490586d4bfa5a073f2c24f680b62e1..2de772b3fb3d7f2daa46feb82c11beea0de0b410 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
@@ -10,6 +10,7 @@
  * Strings required for policy indicators. These must be set at runtime.
  * Chrome OS only strings may be undefined.
  * @type {{
+ *   controlledSettingExtension: string,
  *   controlledSettingPolicy: string,
  *   controlledSettingRecommendedMatches: string,
  *   controlledSettingRecommendedDiffers: string,
@@ -38,8 +39,7 @@ var CrPolicyIndicatorBehavior = {
    * @private
    */
   isIndicatorVisible: function(type) {
-    return type != CrPolicyIndicatorType.NONE &&
-        type != CrPolicyIndicatorType.EXTENSION;
+    return type != CrPolicyIndicatorType.NONE;
   },
 
   /**
@@ -48,26 +48,22 @@ var CrPolicyIndicatorBehavior = {
    * @private
    */
   getPolicyIndicatorIcon: function(type) {
-    var icon = '';
     switch (type) {
-      case CrPolicyIndicatorType.EXTENSION:
       case CrPolicyIndicatorType.NONE:
-        return icon;
+        return '';
+      case CrPolicyIndicatorType.EXTENSION:
+        return 'cr:extension';
       case CrPolicyIndicatorType.PRIMARY_USER:
-        icon = 'cr:group';
-        break;
+        return 'cr:group';
       case CrPolicyIndicatorType.OWNER:
-        icon = 'cr:person';
-        break;
+        return 'cr:person';
       case CrPolicyIndicatorType.USER_POLICY:
       case CrPolicyIndicatorType.DEVICE_POLICY:
       case CrPolicyIndicatorType.RECOMMENDED:
-        icon = 'cr20:domain';
-        break;
+        return 'cr20:domain';
       default:
         assertNotReached();
     }
-    return icon;
   },
 
   /**
@@ -82,6 +78,8 @@ var CrPolicyIndicatorBehavior = {
     if (!CrPolicyStrings)
       return '';  // Tooltips may not be defined, e.g. in OOBE.
     switch (type) {
+      case CrPolicyIndicatorType.EXTENSION:
+        return CrPolicyStrings.controlledSettingExtension;
       case CrPolicyIndicatorType.PRIMARY_USER:
         return CrPolicyStrings.controlledSettingShared.replace('$1', name);
       case CrPolicyIndicatorType.OWNER: