[Extension API Extern Generation] Fix a few bugs in extern generation

tools/json_schema_compiler/js_externs_generator_test.py

 #!/usr/bin/env python
 # Copyright 2015 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.
 
 import idl_schema
 import json_parse
 from js_externs_generator import JsExternsGenerator
 from datetime import datetime
 import model
@@ skipping 25 matching lines @@
     boolean b;
     Greek letter;
     Greek? optionalLetter;
     long[] arr;
     Bar[]? optionalObjArr;
     Greek[] enumArr;
     any[] anythingGoes;
     Bar obj;
     long? maybe;
     (DOMString or Greek or long[]) choice;
+    object plainObj;
   };
 
   callback VoidCallback = void();
 
   callback BazGreekCallback = void(Baz baz, Greek greek);
 
   interface Functions {
     // Does something exciting! And what's more, this is a multiline function
     // comment! It goes onto multiple lines!
     // |baz| : The baz to use.
@@ skipping 51 matching lines @@
  *   num: number,
  *   b: boolean,
  *   letter: !chrome.fakeApi.Greek,
  *   optionalLetter: (!chrome.fakeApi.Greek|undefined),
  *   arr: !Array<number>,
  *   optionalObjArr: (!Array<Bar>|undefined),
  *   enumArr: !Array<!chrome.fakeApi.Greek>,
  *   anythingGoes: !Array<*>,
  *   obj: Bar,
  *   maybe: (number|undefined),
- *   choice: (string|!chrome.fakeApi.Greek|!Array<number>)
+ *   choice: (string|!chrome.fakeApi.Greek|!Array<number>),
+ *   plainObj: Object
  * }}
  * @see https://developer.chrome.com/extensions/fakeApi#type-Baz
  */
 var Baz;
 
 /**
  * Does something exciting! And what's more, this is a multiline function
  * comment! It goes onto multiple lines!
  * @param {Baz} baz The baz to use.
  * @param {function():void} callback
@@ skipping 139 matching lines @@
                               JsExternsGenerator().Generate(namespace).Render())
 
   def testJsonWithInlineObjects(self):
     namespace = self._GetNamespace(fake_json, 'fake_api.json', False)
     self.assertMultiLineEqual(json_expected,
                               JsExternsGenerator().Generate(namespace).Render())
 
 
 if __name__ == '__main__':
   unittest.main()