Lazily load extension API schemas

chrome/common/extensions/api/devtools/panels.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": "devtools.panels",
-    "dependencies": [ "windows" ],
     "nocompile": true,
     "types": [
       {
         "id": "ElementsPanel",
         "type": "object",
         "description": "Represents the Elements panel.",
         "events": [
           {
             "name": "onSelectionChanged",
             "description": "Fired when an object is selected in the panel."
@@ skipping 288 matching lines @@
                 "$ref": "devtools.inspectedWindow.Resource",
                 "description": "A $ref:devtools.inspectedWindow.Resource object for the resource that was clicked."
               }
             ]
           }
         ]
       }
     ]
   }
 ]