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

base/prefs/pref_service.h

 // 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.
 
 // This provides a way to access the application's current preferences.
 
 // Chromium settings and storage represent user-selected preferences and
 // information and MUST not be extracted, overwritten or modified except
 // through Chromium defined APIs.
 
@@ skipping 18 matching lines @@
 class PrefNotifierImpl;
 class PrefObserver;
 class PrefRegistry;
 class PrefValueStore;
 class PrefStore;
 
 namespace base {
 class FilePath;
 }
 
-namespace content {
-class BrowserContext;
-}
-
 namespace subtle {
 class PrefMemberBase;
 class ScopedUserPrefUpdateBase;
 }
 
 // Base class for PrefServices. You can use the base class to read and
 // interact with preferences, but not to register new preferences; for
 // that see e.g. PrefRegistrySimple.
 //
 // Settings and storage accessed through this class represent
@@ skipping 295 matching lines @@
   const base::Value* GetPreferenceValue(const std::string& path) const;
 
   // Local cache of registered Preference objects. The pref_registry_
   // is authoritative with respect to what the types and default values
   // of registered preferences are.
   mutable PreferenceMap prefs_map_;
 
   DISALLOW_COPY_AND_ASSIGN(PrefService);
 };
 
-// Retrieves a PrefService for the given context.
-//
-// TODO(joi): This doesn't really belong here, since it references a
-// content type; probably best to get rid of it completely.
-PrefService* PrefServiceFromBrowserContext(content::BrowserContext* context);
-
 #endif  // BASE_PREFS_PREF_SERVICE_H_