Move UserActivityDetector to ui/base/user_activity/.

ui/base/ui_base.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': [
     {
@@ skipping 351 matching lines @@
         'ui_base_export.h',
         'ui_base_exports.cc',
         'ui_base_paths.cc',
         'ui_base_paths.h',
         'ui_base_switches.cc',
         'ui_base_switches.h',
         'ui_base_switches_util.cc',
         'ui_base_switches_util.h',
         'ui_base_types.cc',
         'ui_base_types.h',
+        'user_activity/user_activity_detector.cc',
+        'user_activity/user_activity_detector.h',
+        'user_activity/user_activity_observer.h',
         'view_prop.cc',
         'view_prop.h',
         'webui/jstemplate_builder.cc',
         'webui/jstemplate_builder.h',
         'webui/web_ui_util.cc',
         'webui/web_ui_util.h',
         'win/accessibility_ids_win.h',
         'win/accessibility_misc_utils.cc',
         'win/accessibility_misc_utils.h',
         'win/atl_module.h',
@@ skipping 407 matching lines @@
            ],
            'variables': {
              'jni_gen_package': 'ui',
            },
            'includes': [ '../../build/jni_generator.gypi' ],
          },
        ],
     }],
   ],
 }