Cleanup: Remove most enable_extensions logic in extensions code.

extensions/common/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': {
     'chromium_code': 1,
-    'main_schema_files': [
+    'schema_files': [
       'app_current_window_internal.idl',
       'app_runtime.idl',
       'app_view_guest_internal.json',
       'app_window.idl',
       'bluetooth.idl',
       'bluetooth_low_energy.idl',
       'bluetooth_private.json',
       'bluetooth_socket.idl',
       'cast_channel.idl',
       'copresence_socket.idl',
@@ skipping 18 matching lines @@
       'system_memory.idl',
       'system_network.idl',
       'system_storage.idl',
       'test.json',
       'usb.idl',
       'virtual_keyboard_private.json',
       'web_request.json',
       'web_view_internal.json',
     ],
     'non_compiled_schema_files': [
-    ],
-    'main_non_compiled_schema_files': [
       'web_request_internal.json',
     ],
-    # TODO(thestig) Do not include this file in non-extensions builds.
-    # Then the conditional and else block can go away.
-    # Do the same for extensions/common/api/schemas.gni.
-    'conditions': [
-      ['enable_extensions==1', {
-        'non_compiled_schema_files': [
-          '<@(main_non_compiled_schema_files)',
-        ],
-        'schema_files': [
-          '<@(main_schema_files)',
-        ],
-      }, {
-        'schema_files': [
-        ],
-      }],
-    ],
     'cc_dir': 'extensions/common/api',
     'root_namespace': 'extensions::core_api::%(namespace)s',
     'impl_dir_': 'extensions/browser/api',
   },
 }