Move PrivetV3ContextGetter into separate file next to privet_v3_session

chrome/chrome_browser_extensions.gypi

 # Copyright (c) 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': {
     'chrome_browser_extensions_chromeos_sources': [
       'browser/extensions/api/cast_devices_private/cast_devices_private_api.cc',
       'browser/extensions/api/cast_devices_private/cast_devices_private_api.h',
       'browser/extensions/api/certificate_provider/certificate_provider_api.cc',
@@ skipping 275 matching lines @@
       'browser/extensions/api/file_handlers/app_file_handler_util.cc',
       'browser/extensions/api/file_handlers/app_file_handler_util.h',
       'browser/extensions/api/file_handlers/mime_util.cc',
       'browser/extensions/api/file_handlers/mime_util.h',
       'browser/extensions/api/file_system/file_system_api.cc',
       'browser/extensions/api/file_system/file_system_api.h',
       'browser/extensions/api/font_settings/font_settings_api.cc',
       'browser/extensions/api/font_settings/font_settings_api.h',
       'browser/extensions/api/gcd_private/gcd_private_api.cc',
       'browser/extensions/api/gcd_private/gcd_private_api.h',
+      'browser/extensions/api/gcd_private/privet_v3_context_getter.cc',
+      'browser/extensions/api/gcd_private/privet_v3_context_getter.h',
       'browser/extensions/api/gcd_private/privet_v3_session.cc',
       'browser/extensions/api/gcd_private/privet_v3_session.h',
       'browser/extensions/api/gcm/gcm_api.cc',
       'browser/extensions/api/gcm/gcm_api.h',
       'browser/extensions/api/history/history_api.cc',
       'browser/extensions/api/history/history_api.h',
       'browser/extensions/api/hotword_private/hotword_private_api.cc',
       'browser/extensions/api/hotword_private/hotword_private_api.h',
       'browser/extensions/api/i18n/i18n_api.cc',
       'browser/extensions/api/i18n/i18n_api.h',
@@ skipping 844 matching lines @@
           ],
         }, {  # use_brlapi==0
           'sources': [
             'browser/extensions/api/braille_display_private/braille_controller_stub.cc',
           ],
         }],
       ],
     },
   ],
 }