Extract //device/usb mocks so that they can be shared.

chrome/chrome_tests_unit.gypi

 # Copyright 2012 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_unit_tests_sources': [
       '../components/autofill/content/renderer/test_password_autofill_agent.cc',
       '../components/autofill/content/renderer/test_password_autofill_agent.h',
       '../components/autofill/content/renderer/test_password_generation_agent.cc',
       '../components/autofill/content/renderer/test_password_generation_agent.h',
@@ skipping 2180 matching lines @@
         ['enable_one_click_signin==1', {
           'sources': [
             'browser/ui/sync/one_click_signin_sync_observer_unittest.cc',
             'browser/ui/sync/one_click_signin_sync_starter_unittest.cc',
           ],
         }],
         ['enable_extensions==1', {
           'sources': [ '<@(chrome_unit_tests_extensions_sources)' ],
           'dependencies': [
             'common/extensions/api/api.gyp:chrome_api',
+            '../device/usb/usb.gyp:device_usb_mocks',
             '../components/components.gyp:audio_modem_test_support',
             '../extensions/extensions_resources.gyp:extensions_resources',
             '../extensions/extensions_strings.gyp:extensions_strings',
           ],
           'conditions': [
             ['configuration_policy==1', {
               'sources': [ '<@(chrome_unit_tests_extensions_policy_sources)' ],
             }],
             ['chromeos == 0', {
               'sources': [
@@ skipping 575 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }