Update GN build files for new prefs location.

components/rappor/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.
 
 # GYP version: components/rappor.gypi:rappor
 source_set("rappor") {
   sources = [
     "bloom_filter.cc",
     "bloom_filter.h",
     "byte_vector_utils.cc",
@@ skipping 20 matching lines @@
     "sampler.cc",
     "sampler.h",
   ]
 
   public_deps = [
     "//components/rappor/proto",
   ]
 
   deps = [
     "//base",
-    "//base:prefs",
     "//components/data_use_measurement/core",
     "//components/metrics",
+    "//components/prefs",
     "//components/variations",
     "//crypto",
     "//net",
     "//third_party/smhasher:cityhash",
   ]
 }
 
 # GYP version: components/rappor.gypi:rappor_test_support
 static_library("test_support") {
   testonly = true
   sources = [
     "test_log_uploader.cc",
     "test_log_uploader.h",
     "test_rappor_service.cc",
     "test_rappor_service.h",
   ]
 
   public_deps = [
     ":rappor",
   ]
   deps = [
     "//base",
-    "//base:prefs_test_support",
+    "//components/prefs:test_support",
   ]
 }
 
 source_set("unit_tests") {
   testonly = true
   sources = [
     "bloom_filter_unittest.cc",
     "byte_vector_utils_unittest.cc",
     "log_uploader_unittest.cc",
     "rappor_metric_unittest.cc",
     "rappor_prefs_unittest.cc",
     "rappor_service_unittest.cc",
     "rappor_utils_unittest.cc",
     "sampler_unittest.cc",
   ]
 
   deps = [
     ":rappor",
     ":test_support",
     "//base",
-    "//base:prefs_test_support",
     "//base/test:test_support",
     "//components/metrics",
+    "//components/prefs:test_support",
     "//net:test_support",
     "//testing/gtest",
     "//url",
   ]
 }