Reset user data directory and disk cache directory after downgrade.

chrome/chrome_tests.gypi

 # Copyright 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': {
     'build_angle_deqp_tests%': 0,
     'chrome_browser_extensions_test_support_sources': [
       # A list of sources which is shared between different browser tests.
       'browser/apps/app_browsertest_util.cc',
       'browser/apps/app_browsertest_util.h',
@@ skipping 1134 matching lines @@
       '../ui/resources/cursors/aliasb.cur',
       '../ui/resources/cursors/cell.cur',
       '../ui/resources/cursors/col_resize.cur',
       '../ui/resources/cursors/copy.cur',
       '../ui/resources/cursors/none.cur',
       '../ui/resources/cursors/row_resize.cur',
       '../ui/resources/cursors/vertical_text.cur',
       '../ui/resources/cursors/zoom_in.cur',
       '../ui/resources/cursors/zoom_out.cur',
       'app/chrome_dll.rc',
+      'browser/downgrade/user_data_downgrade_browsertest.cc',
       'test/data/resource.rc',
     ],
     # Cross-platform (except Mac) views interactive tests.
     # TODO(tapted): Move these to chrome_interactive_ui_test_views_sources when
     # the corresponding files are moved in chrome_browser_ui.gypi (i.e. out of
     # chrome_browser_ui_views_non_mac_sources).
     'chrome_interactive_ui_test_views_non_mac_sources': [
       'browser/ui/views/bookmarks/bookmark_bar_view_test.cc',
       'browser/ui/views/bookmarks/bookmark_bar_view_test_helper.h',
       'browser/ui/views/certificate_selector_browsertest.cc',
@@ skipping 2413 matching lines @@
             'browser',
           ],
           'sources': [
             'tools/service_discovery_sniffer/service_discovery_sniffer.cc',
             'tools/service_discovery_sniffer/service_discovery_sniffer.h',
           ],
         }]
     }],
   ],  # 'conditions'
 }