Add a couple of notifications related settings to app/extensions sync:

chrome/browser/sync/protocol/proto_value_conversions.h

Index: chrome/browser/sync/protocol/proto_value_conversions.h
===================================================================
--- chrome/browser/sync/protocol/proto_value_conversions.h	(revision 107300)
+++ chrome/browser/sync/protocol/proto_value_conversions.h	(working copy)
@@ -13,6 +13,7 @@
 }
 
 namespace sync_pb {
+class AppNotificationSettings;
 class AppNotificationSpecifics;
 class AppSpecifics;
 class AutofillProfileSpecifics;
@@ -54,6 +55,10 @@
 base::DictionaryValue* EncryptedDataToValue(
     const sync_pb::EncryptedData& encrypted_data);
 
+// Sub-protocol of AppSpecifics.
+base::DictionaryValue* AppSettingsToValue(
+    const sync_pb::AppNotificationSettings& app_notification_settings);
+
 // Sub-protocols of SessionSpecifics.
 
 base::DictionaryValue* SessionHeaderToValue(