Introduce //components/user_prefs, use to eliminate c/b/prefs dependency in Autofill.

chrome/browser/web_resource/notification_promo.cc

 // Copyright (c) 2012 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 "chrome/browser/web_resource/notification_promo.h"
 
 #include <cmath>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "base/rand_util.h"
 #include "base/string_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/prefs/pref_registry_syncable.h"
 #include "chrome/browser/web_resource/promo_resource_service.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/pref_names.h"
+#include "components/user_prefs/pref_registry_syncable.h"
 #include "content/public/browser/user_metrics.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/url_util.h"
 
 #if defined(OS_ANDROID)
 #include "base/command_line.h"
 #include "chrome/common/chrome_switches.h"
 #endif  // defined(OS_ANDROID)
 
 using content::UserMetricsAction;
@@ skipping 414 matching lines @@
   if (group_ < initial_segment_)
     return start_;
   return start_ +
       std::ceil(static_cast<float>(group_ - initial_segment_ + 1) / increment_)
       * time_slice_;
 }
 
 double NotificationPromo::EndTime() const {
   return end_;
 }