Lazily load extension API schemas

chrome/common/extensions/api/proxy.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": "proxy",
-    "dependencies": [ "types" ],
     "types": [
       {
         "id": "ProxyServer",
         "type": "object",
         "description": "An object encapsulating a single proxy server's specification.",
         "properties": {
           "scheme": {"type": "string", "optional": true, "enum": ["http", "https", "socks4", "socks5"], "description": "The scheme (protocol) of the proxy server itself. Defaults to 'http'."},
           "host": {"type": "string", "description": "The URI of the proxy server. This must be an ASCII hostname (in Punycode format). IDNA is not supported, yet."},
           "port": {"type": "integer", "optional": true, "description": "The port of the proxy server. Defaults to a port that depends on the scheme."}
         }
@@ skipping 68 matching lines @@
                 "type": "string",
                 "description": "Additional details about the error such as a JavaScript runtime error."
               }
             }
           }
         ]
       }
     ]
   }
 ]