Add sampling of unknown filetypes in download protection.

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 743 matching lines @@
       'browser/speech/extension_api/extension_manifests_tts_unittest.cc',
       'browser/speech/tts_controller_unittest.cc',
     ],
     'chrome_unit_tests_notifications_sources': [
       'browser/notifications/desktop_notification_profile_util_unittest.cc',
       'browser/notifications/message_center_notifications_unittest.cc',
       'browser/notifications/message_center_settings_controller_unittest.cc',
       'browser/notifications/notification_permission_context_unittest.cc',
       'browser/notifications/platform_notification_service_unittest.cc',
     ],
-     # Used by Full Safe Browsing (safe_browsing==1) and Mobile Safe
-     # Browsing (==2) modes.
+     # Used by Full Safe Browsing (safe_browsing==1)
+     # and by Mobile Safe Browsing (==2) modes.
     'chrome_unit_tests_shared_safe_browsing_sources': [
       'browser/safe_browsing/ping_manager_unittest.cc',
       'browser/safe_browsing/safe_browsing_blocking_page_unittest.cc',
       'browser/safe_browsing/threat_details_unittest.cc',
       'browser/safe_browsing/ui_manager_unittest.cc',
       'common/safe_browsing/file_type_policies_unittest.cc',
+      'common/safe_browsing/file_type_policies_test_util.cc',
+      'common/safe_browsing/file_type_policies_test_util.h',
      ],
     'chrome_unit_tests_full_safe_browsing_sources': [
       'browser/safe_browsing/browser_feature_extractor_unittest.cc',
       'browser/safe_browsing/chunk_range_unittest.cc',
       'browser/safe_browsing/client_side_detection_host_unittest.cc',
       'browser/safe_browsing/client_side_detection_service_unittest.cc',
       'browser/safe_browsing/client_side_model_loader_unittest.cc',
       'browser/safe_browsing/download_feedback_service_unittest.cc',
       'browser/safe_browsing/download_feedback_unittest.cc',
       'browser/safe_browsing/download_protection_service_unittest.cc',
@@ skipping 2233 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }