Add webusb notification UI unit tests

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': [
       # histograms.xml is analyzed by AboutFlagsHistogramTest, so this
       # dependency is needed to make commit bots run unit_tests on
       # histograms.xml changes.
       '../tools/metrics/histograms/histograms.xml',
@@ skipping 1451 matching lines @@
       'browser/ui/webui/media_router/media_router_test.h',
       'browser/ui/webui/media_router/media_router_webui_message_handler_unittest.cc',
       'browser/ui/webui/media_router/query_result_manager_unittest.cc',
     ],
     # Everything but Android and iOS (iOS is handled separately).
     'chrome_unit_tests_non_android_sources': [
       # Bookmark export/import are handled via the BookmarkColumns
       # ContentProvider.
       'browser/bookmarks/bookmark_html_writer_unittest.cc',
       'browser/browser_commands_unittest.cc',
+      'browser/chrome_webusb_browser_client_unittest.cc',
       'browser/diagnostics/diagnostics_controller_unittest.cc',
       'browser/diagnostics/diagnostics_model_unittest.cc',
       'browser/download/download_commands_unittest.cc',
       'browser/download/download_shelf_unittest.cc',
       'browser/engagement/site_engagement_eviction_policy_unittest.cc',
       'browser/engagement/site_engagement_service_unittest.cc',
       'browser/first_run/first_run_unittest.cc',
       'browser/font_family_cache_unittest.cc',
       'browser/importer/firefox_profile_lock_unittest.cc',
       'browser/importer/profile_writer_unittest.cc',
@@ skipping 1444 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }