Trigger chrome.storage.onChanged events for policy updates on the 'managed' namespace.

chrome/common/extensions/api/storage.json

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 [
   {
     "namespace": "storage",
     "unprivileged": true,
     "types": [
       {
@@ skipping 145 matching lines @@
         "parameters": [
           {
             "name": "changes",
             "type": "object",
             "additionalProperties": { "$ref": "StorageChange" },
             "description": "Object mapping each key that changed to its corresponding <a href='#type-StorageChange'>StorageChange</a> for that item."
           },
           {
             "name": "areaName",
             "type": "string",
-            "description": "The name of the storage area (\"sync\" or \"local\") the changes are for."
+            "description": "The name of the storage area (\"sync\", \"local\" or \"managed\") the changes are for."
           }
         ]
       }
     ],
     "properties": {
       "sync": {
         "$ref": "StorageArea",
         "description": "Items under the \"sync\" storage area are synced using Chrome Sync.",
         "value": [ "sync" ],
         "properties": {
@@ skipping 31 matching lines @@
         }
       },
       "managed": {
         "$ref": "StorageArea",
         "description": "Items under the \"managed\" storage area are set by the domain administrator, and are read-only by the extension; trying to modify this namespace results in an error.",
         "value": [ "managed" ]
       }
     }
   }
 ]