Update GN build files for new prefs location.

components/policy/core/browser/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 
 # GYP version: components/policy.gypi:policy_component_core_browser
 source_set("browser") {
   visibility = [ "//components/policy/*" ]
   sources = [
     # Note that these sources are always included, even for builds that disable
     # policy. Most source files should go in the conditional sources list
     # below. url_blacklist_manager.h is used by managed mode.
     "url_blacklist_manager.cc",
     "url_blacklist_manager.h",
   ]
 
   defines = [ "POLICY_COMPONENT_IMPLEMENTATION" ]
 
   deps = [
     "//base",
-    "//base:prefs",
     "//base/third_party/dynamic_annotations",
     "//components/bookmarks/managed",
     "//components/keyed_service/core",
     "//components/policy/core/common",
     "//components/pref_registry",
+    "//components/prefs",
     "//components/strings",
     "//components/url_matcher",
     "//ui/base",
   ]
 
   if (is_android) {
     sources += [
       "android/android_combined_policy_provider.cc",
       "android/android_combined_policy_provider.h",
       "android/component_jni_registrar.cc",
@@ skipping 51 matching lines @@
       "autofill_policy_handler_unittest.cc",
       "browser_policy_connector_unittest.cc",
       "configuration_policy_handler_unittest.cc",
       "configuration_policy_pref_store_unittest.cc",
       "proxy_policy_handler_unittest.cc",
       "url_blacklist_manager_unittest.cc",
       "url_blacklist_policy_handler_unittest.cc",
     ]
     deps = [
       "//base",
-      "//base:prefs_test_support",
       "//components/autofill/core/common",
       "//components/policy",
       "//components/policy:policy_component_test_support",
+      "//components/prefs:test_support",
       "//components/proxy_config",
       "//components/url_formatter",
       "//google_apis",
       "//net",
       "//testing/gmock",
       "//testing/gtest",
     ]
   }
 }