Update GN build files for new prefs location.

components/data_reduction_proxy/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.
 
 browser_sources = [
   "data_reduction_proxy_bypass_protocol.cc",
   "data_reduction_proxy_bypass_protocol.h",
   "data_reduction_proxy_bypass_stats.cc",
   "data_reduction_proxy_bypass_stats.h",
   "data_reduction_proxy_compression_stats.cc",
@@ skipping 39 matching lines @@
   "db_data_owner.cc",
   "db_data_owner.h",
 ]
 
 if (is_android) {
   source_set("browser_small") {
     sources = browser_sources
 
     deps = [
       "//base",
-      "//base:prefs",
       "//components/data_reduction_proxy/core/common:common_small",
       "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
       "//components/pref_registry",
+      "//components/prefs",
       "//components/variations",
       "//crypto",
       "//google_apis:google_apis_small",
       "//net:net_small",
       "//url:url_lib_use_icu_alternatives_on_android",
     ]
   }
 }
 
 source_set("browser") {
   sources = browser_sources
   sources += [
     "data_store_impl.cc",
     "data_store_impl.h",
   ]
 
   deps = [
     "//base",
-    "//base:prefs",
     "//components/data_reduction_proxy/core/common",
     "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
     "//components/pref_registry",
+    "//components/prefs",
     "//components/variations",
     "//crypto",
     "//google_apis",
     "//net",
     "//third_party/leveldatabase",
     "//url",
   ]
 
   defines = [ "USE_GOOGLE_API_KEYS" ]
   if (!is_ios) {
@@ skipping 14 matching lines @@
     "data_reduction_proxy_test_utils.h",
   ]
 
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   public_deps = [
     ":browser",
   ]
   deps = [
     "//base",
-    "//base:prefs_test_support",
     "//components/data_reduction_proxy/core/common",
     "//components/data_reduction_proxy/core/common:test_support",
+    "//components/prefs:test_support",
     "//net",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
@@ skipping 16 matching lines @@
     "data_reduction_proxy_tamper_detection_unittest.cc",
     "data_usage_store_unittest.cc",
   ]
 
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   deps = [
     ":browser",
     ":test_support",
     "//base",
-    "//base:prefs_test_support",
     "//base/test:test_support",
     "//components/data_reduction_proxy/core/common:test_support",
     "//components/data_reduction_proxy/proto:data_reduction_proxy_proto",
+    "//components/prefs:test_support",
     "//components/variations",
     "//net:test_support",
     "//testing/gmock",
     "//testing/gtest",
   ]
 }