Remove experimental permission from infobars API and moving it to dev channel

chrome/common/extensions/api/infobars.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": "experimental.infobars",
+    "namespace": "infobars",
     "description": "Use the <code>chrome.infobars</code> API to add a horizontal panel just above a tab's contents. See the screenshot below.",
     "compiler_options": {
       "implemented_in": "chrome/browser/infobars/infobar_extension_api.h"
     },
     "types": [],
     "functions": [
       {
         "name": "show",
         "type": "function",
         "description": "Shows an infobar in the specified tab. The infobar will be closed automatically when the tab navigates. Use window.close() to close the infobar before then.",
@@ skipping 27 matching lines @@
               {
                 "name": "window", "$ref": "windows.Window", "description": "Contains details about the window in which the infobar was created."
               }
             ]
           }
         ]
       }
     ]
   }
 ]