[Sync] Rename syncable_prefs to sync_preferences.

components/sync_preferences/pref_service_syncable_observer.h

 // Copyright 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.
 
-#ifndef COMPONENTS_SYNCABLE_PREFS_PREF_SERVICE_SYNCABLE_OBSERVER_H_
-#define COMPONENTS_SYNCABLE_PREFS_PREF_SERVICE_SYNCABLE_OBSERVER_H_
+#ifndef COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_OBSERVER_H_
+#define COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_OBSERVER_H_
 
-namespace syncable_prefs {
+namespace sync_preferences {
 
 class PrefServiceSyncableObserver {
  public:
   // Invoked when PrefService::IsSyncing() changes.
   virtual void OnIsSyncingChanged() = 0;
 
  protected:
   virtual ~PrefServiceSyncableObserver() {}
 };
 
-}  // namespace syncable_prefs
+}  // namespace sync_preferences
 
-#endif  // COMPONENTS_SYNCABLE_PREFS_PREF_SERVICE_SYNCABLE_OBSERVER_H_
+#endif  // COMPONENTS_SYNC_PREFERENCES_PREF_SERVICE_SYNCABLE_OBSERVER_H_