Make PrinterProviderAPI a pure interface

extensions/extensions.gypi

 # Copyright 2015 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': {
     'extensions_common_constants_sources': [
       'common/constants.cc',
       'common/constants.h',
     ],
@@ skipping 369 matching lines @@
       'browser/api/networking_private/networking_private_event_router.h',
       'browser/api/networking_private/networking_private_event_router_chromeos.cc',
       'browser/api/networking_private/networking_private_event_router_factory.cc',
       'browser/api/networking_private/networking_private_event_router_factory.h',
       'browser/api/power/power_api.cc',
       'browser/api/power/power_api.h',
       'browser/api/power/power_api_manager.cc',
       'browser/api/power/power_api_manager.h',
       'browser/api/printer_provider/printer_provider_api.cc',
       'browser/api/printer_provider/printer_provider_api.h',
+      'browser/api/printer_provider/printer_provider_api_factory.cc',
+      'browser/api/printer_provider/printer_provider_api_factory.h',
+      'browser/api/printer_provider/printer_provider_print_job.cc',
+      'browser/api/printer_provider/printer_provider_print_job.h',
       'browser/api/printer_provider_internal/printer_provider_internal_api.cc',
       'browser/api/printer_provider_internal/printer_provider_internal_api.h',
       'browser/api/printer_provider_internal/printer_provider_internal_api_observer.h',
       'browser/api/runtime/runtime_api.cc',
       'browser/api/runtime/runtime_api.h',
       'browser/api/runtime/runtime_api_delegate.cc',
       'browser/api/runtime/runtime_api_delegate.h',
       'browser/api/serial/serial_api.cc',
       'browser/api/serial/serial_api.h',
       'browser/api/serial/serial_connection.cc',
@@ skipping 615 matching lines @@
       'test/result_catcher.h',
       'test/test_content_utility_client.cc',
       'test/test_content_utility_client.h',
       'test/test_extensions_client.cc',
       'test/test_extensions_client.h',
       'test/test_permission_message_provider.cc',
       'test/test_permission_message_provider.h',
     ],
   },
 }