Remove BrowserThread dependency from usb_service.

extensions/shell/app_shell.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
       'target_name': 'app_shell_lib',
       'type': 'static_library',
       'defines!': ['CONTENT_IMPLEMENTATION'],
       'dependencies': [
         'app_shell_version_header',
         '<(DEPTH)/base/base.gyp:base',
         '<(DEPTH)/base/base.gyp:base_prefs_test_support',
         '<(DEPTH)/components/components.gyp:omaha_query_params',
         '<(DEPTH)/components/components.gyp:pref_registry',
         '<(DEPTH)/components/components.gyp:user_prefs',
         '<(DEPTH)/content/content.gyp:content',
         '<(DEPTH)/content/content.gyp:content_gpu',
         '<(DEPTH)/content/content.gyp:content_ppapi_plugin',
         '<(DEPTH)/content/content_shell_and_tests.gyp:content_shell_lib',
+        '<(DEPTH)/device/core/core.gyp:device_core',
         '<(DEPTH)/device/hid/hid.gyp:device_hid',
         '<(DEPTH)/extensions/browser/api/api_registration.gyp:extensions_api_registration',
         '<(DEPTH)/extensions/common/api/api.gyp:extensions_api',
         '<(DEPTH)/extensions/extensions.gyp:extensions_browser',
         '<(DEPTH)/extensions/extensions.gyp:extensions_common',
         '<(DEPTH)/extensions/extensions.gyp:extensions_renderer',
         '<(DEPTH)/extensions/extensions.gyp:extensions_shell_and_test_pak',
         '<(DEPTH)/extensions/extensions_resources.gyp:extensions_resources',
         '<(DEPTH)/extensions/shell/browser/api/api_registration.gyp:shell_api_registration',
         '<(DEPTH)/extensions/shell/common/api/api.gyp:shell_api',
@@ skipping 29 matching lines @@
         'browser/shell_app_window_controller.h',
         'browser/shell_browser_context.cc',
         'browser/shell_browser_context.h',
         'browser/shell_browser_main_delegate.h',
         'browser/shell_browser_main_parts.cc',
         'browser/shell_browser_main_parts.h',
         'browser/shell_content_browser_client.cc',
         'browser/shell_content_browser_client.h',
         'browser/shell_desktop_controller.cc',
         'browser/shell_desktop_controller.h',
+        'browser/shell_device_client.cc',
+        'browser/shell_device_client.h',
         'browser/shell_extension_host_delegate.cc',
         'browser/shell_extension_host_delegate.h',
         'browser/shell_extension_system.cc',
         'browser/shell_extension_system.h',
         'browser/shell_extension_system_factory.cc',
         'browser/shell_extension_system_factory.h',
         'browser/shell_extension_web_contents_observer.cc',
         'browser/shell_extension_web_contents_observer.h',
         'browser/shell_extensions_browser_client.cc',
         'browser/shell_extensions_browser_client.h',
@@ skipping 169 matching lines @@
             '<@(_outputs)',
           ],
           'includes': [
             '../../build/util/version.gypi',
           ],
         },
       ],
     },
   ],  # targets
 }