[Sync] Rename syncable_prefs to sync_preferences.

chrome/browser/prefs/chrome_pref_service_factory.h

Index: chrome/browser/prefs/chrome_pref_service_factory.h
diff --git a/chrome/browser/prefs/chrome_pref_service_factory.h b/chrome/browser/prefs/chrome_pref_service_factory.h
index 71d130c5df5b06384b1fdc382e7ede8ac7105574..ca3e38f42176bdafe6e273c4752a5a143a02e148 100644
--- a/chrome/browser/prefs/chrome_pref_service_factory.h
+++ b/chrome/browser/prefs/chrome_pref_service_factory.h
@@ -20,7 +20,7 @@ namespace policy {
 class PolicyService;
 }
 
-namespace syncable_prefs {
+namespace sync_preferences {
 class PrefServiceSyncable;
 }
 
@@ -72,7 +72,7 @@ std::unique_ptr<PrefService> CreateLocalState(
     const scoped_refptr<PrefRegistry>& pref_registry,
     bool async);
 
-std::unique_ptr<syncable_prefs::PrefServiceSyncable> CreateProfilePrefs(
+std::unique_ptr<sync_preferences::PrefServiceSyncable> CreateProfilePrefs(
     const base::FilePath& pref_filename,
     base::SequencedTaskRunner* pref_io_task_runner,
     TrackedPreferenceValidationDelegate* validation_delegate,