Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/chromeos/language_preferences.h

Index: chrome/browser/chromeos/language_preferences.h
diff --git a/chrome/browser/chromeos/language_preferences.h b/chrome/browser/chromeos/language_preferences.h
index 07b15c8be93e171670715707734ac957815b6192..abde39fa426c8776ce0445cca431c07a2549a380 100644
--- a/chrome/browser/chromeos/language_preferences.h
+++ b/chrome/browser/chromeos/language_preferences.h
@@ -7,7 +7,7 @@
 
 #include <stddef.h>  // For size_t
 
-#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/prefs/pref_registry_syncable.h"
 
 class PrefRegistrySimple;
 
@@ -38,7 +38,7 @@ struct LanguageMultipleChoicePreference {
     int item_message_id;  // Resource grd ID for the combobox item.
   } values_and_ids[kMaxItems];
   int label_message_id;  // Resource grd ID for the label.
-  PrefServiceSyncable::PrefSyncStatus sync_status;
+  PrefRegistrySyncable::PrefSyncStatus sync_status;
 };
 
 // The struct is used for preferences of boolean values, like switches to
@@ -48,7 +48,7 @@ struct LanguageBooleanPrefs {
   bool default_pref_value;
   const char* ibus_config_name;
   int message_id;
-  PrefServiceSyncable::PrefSyncStatus sync_status;
+  PrefRegistrySyncable::PrefSyncStatus sync_status;
 };
 
 // The struct is used for preferences of integer range values, like the
@@ -60,7 +60,7 @@ struct LanguageIntegerRangePreference {
   int max_pref_value;
   const char* ibus_config_name;
   int message_id;
-  PrefServiceSyncable::PrefSyncStatus sync_status;
+  PrefRegistrySyncable::PrefSyncStatus sync_status;
 };
 
 // ---------------------------------------------------------------------------
@@ -125,7 +125,7 @@ struct PinyinIntegerPref {
   const char* pref_name;  // Chrome preference name.
   int default_pref_value;
   const char* ibus_config_name;
-  PrefServiceSyncable::PrefSyncStatus sync_status;
+  PrefRegistrySyncable::PrefSyncStatus sync_status;
   // TODO(yusukes): Add message_id if needed.
 };