Add some remoting targets to GN build.

extensions/extensions.gyp

 # Copyright 2013 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 255 matching lines @@
       ],
       'include_dirs': [
         '..',
         '<(INTERMEDIATE_DIR)',
         # Needed to access generated API headers.
         '<(SHARED_INTERMEDIATE_DIR)',
         # Needed for grit.
         '<(SHARED_INTERMEDIATE_DIR)/chrome',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'browser/admin_policy.cc',
         'browser/admin_policy.h',
         # NOTE: When moving an API out of Chrome be sure to verify that the
         # Android build still compiles. See conditions below.
         'browser/api/api_resource.cc',
         'browser/api/api_resource.h',
         'browser/api/api_resource_manager.h',
         'browser/api/app_runtime/app_runtime_api.cc',
         'browser/api/app_runtime/app_runtime_api.h',
         'browser/api/app_view/app_view_internal_api.cc',
@@ skipping 670 matching lines @@
           'browser/api/cast_channel/logging.proto'
       ],
       'variables': {
           'proto_in_dir': 'browser/api/cast_channel',
           'proto_out_dir': 'extensions/browser/api/cast_channel',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ]
 }