Delete the audio modem and copresence private APIs.

chrome/common/extensions/api/schemas.gypi

 # Copyright 2014 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.
 
 {
   'sources': [
     '<@(schema_files)',
   ],
   'variables': {
     'main_schema_files': [
       'accessibility_features.json',
       'accessibility_private.json',
       'activity_log_private.json',
-      'audio_modem.idl',
       'autofill_private.idl',
       'automation.idl',
       'automation_internal.idl',
       'autotest_private.idl',
       'bluetooth_low_energy.idl',
       'bookmark_manager_private.json',
       'bookmarks.json',
       'braille_display_private.idl',
       'browser.idl',
       'chrome_web_view_internal.json',
       'cloud_print_private.json',
       'command_line_private.json',
       'content_settings.json',
       'context_menus_internal.json',
       'context_menus.json',
       'cookies.json',
-      'copresence_private.idl',
       'cryptotoken_private.idl',
       'dashboard_private.json',
       'data_reduction_proxy.json',
       'debugger.json',
       'desktop_capture.json',
       'developer_private.idl',
       'dial.idl',
       'downloads.idl',
       'downloads_internal.idl',
       'easy_unlock_private.idl',
@@ skipping 166 matching lines @@
           '<@(app_list_schema_files)',
         ],
       }],
     ],
     'cc_dir': 'chrome/common/extensions/api',
     'root_namespace': 'extensions::api::%(namespace)s',
     'bundle_name': 'Chrome',
     'impl_dir_': 'chrome/browser/extensions/api',
   },
 }