Revert of Delete base/prefs and update callers to use components.

components/metrics/cloned_install_detector_unittest.cc

 // 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.
 
 #include "components/metrics/cloned_install_detector.h"
 
+#include "base/prefs/testing_pref_service.h"
 #include "components/metrics/machine_id_provider.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/metrics/metrics_state_manager.h"
-#include "components/prefs/testing_pref_service.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace metrics {
 
 namespace {
 
 const std::string kTestRawId = "test";
 // Hashed machine id for |kTestRawId|.
 const int kTestHashedId = 2216819;
 
@@ skipping 23 matching lines @@
 
   scoped_ptr<ClonedInstallDetector> detector(
       new ClonedInstallDetector(MachineIdProvider::CreateInstance()));
 
   detector->SaveMachineId(&prefs, kTestRawId);
 
   EXPECT_TRUE(prefs.GetBoolean(prefs::kMetricsResetIds));
 }
 
 }  // namespace metrics