Disable the managed storage API behind a flag for M22.

chrome/common/extensions/api/storage.json

Index: chrome/common/extensions/api/storage.json
diff --git a/chrome/common/extensions/api/storage.json b/chrome/common/extensions/api/storage.json
index c2abffcfb8fc41bcb3696a5387a14fd6d28e452d..60ad8b1c9632de805ecf4d39dcbb0f01956316e5 100644
--- a/chrome/common/extensions/api/storage.json
+++ b/chrome/common/extensions/api/storage.json
@@ -163,7 +163,7 @@
           {
             "name": "areaName",
             "type": "string",
-            "description": "The name of the storage area (\"sync\", \"local\" or \"managed\") the changes are for."
+            "description": "The name of the storage area (\"sync\" or \"local\") the changes are for."
           }
         ]
       }
@@ -210,7 +210,8 @@
       "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" ]
+        "value": [ "managed" ],
+        "nodoc": true
       }
     }
   }