Move the chromeHidden.toJSON paranoia out of event.js and into json.js, a new

chrome/chrome_renderer.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'renderer',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 142 matching lines @@
         'renderer/resources/extensions/context_menus_custom_bindings.js',
         'renderer/resources/extensions/declarative_content_custom_bindings.js',
         'renderer/resources/extensions/declarative_webrequest_custom_bindings.js',
         'renderer/resources/extensions/event.js',
         'renderer/resources/extensions/experimental.offscreenTabs_custom_bindings.js',
         'renderer/resources/extensions/extension_custom_bindings.js',
         'renderer/resources/extensions/file_browser_handler_custom_bindings.js',
         'renderer/resources/extensions/file_browser_private_custom_bindings.js',
         'renderer/resources/extensions/greasemonkey_api.js',
         'renderer/resources/extensions/input.ime_custom_bindings.js',
+        'renderer/resources/extensions/json.js',
         'renderer/resources/extensions/json_schema.js',
         'renderer/resources/extensions/last_error.js',
         'renderer/resources/extensions/miscellaneous_bindings.js',
         'renderer/resources/extensions/omnibox_custom_bindings.js',
         'renderer/resources/extensions/page_action_custom_bindings.js',
         'renderer/resources/extensions/page_actions_custom_bindings.js',
         'renderer/resources/extensions/page_capture_custom_bindings.js',
         'renderer/resources/extensions/platform_app.js',
         'renderer/resources/extensions/runtime_custom_bindings.js',
         'renderer/resources/extensions/schema_generated_bindings.js',
@@ skipping 186 matching lines @@
               'export_dependent_settings': [
                 '<(allocator_target)',
               ],
             }],
           ],
         }],
       ],
     },
   ],
 }