[Sync] Add history delete directive type

sync/syncable/model_type.cc

Index: sync/syncable/model_type.cc
diff --git a/sync/syncable/model_type.cc b/sync/syncable/model_type.cc
index e4993a47017f3a739a07d1a522438e1bea6be43f..f4e23612227752077388b068cc4e3dfd633a70f7 100644
--- a/sync/syncable/model_type.cc
+++ b/sync/syncable/model_type.cc
@@ -73,6 +73,9 @@ void AddDefaultFieldValue(ModelType datatype,
     case APP_NOTIFICATIONS:
       specifics->mutable_app_notification();
       break;
+    case HISTORY_DELETE_DIRECTIVES:
+      specifics->mutable_history_delete_directive();
+      break;
     case DEVICE_INFO:
       specifics->mutable_device_info();
       break;
@@ -138,6 +141,8 @@ int GetSpecificsFieldNumberFromModelType(ModelType model_type) {
     case APP_NOTIFICATIONS:
       return sync_pb::EntitySpecifics::kAppNotificationFieldNumber;
       break;
+    case HISTORY_DELETE_DIRECTIVES:
+      return sync_pb::EntitySpecifics::kHistoryDeleteDirectiveFieldNumber;
     case DEVICE_INFO:
       return sync_pb::EntitySpecifics::kDeviceInfoFieldNumber;
       break;
@@ -158,7 +163,7 @@ FullModelTypeSet ToFullModelTypeSet(ModelTypeSet in) {
   return out;
 }
 
-// Note: keep this consistent with GetModelType in syncable.cc!
+// Note: keep this consistent with GetModelType in entry.cc!
 ModelType GetModelType(const sync_pb::SyncEntity& sync_entity) {
   DCHECK(!IsRoot(sync_entity));  // Root shouldn't ever go over the wire.
 
@@ -233,6 +238,9 @@ ModelType GetModelTypeFromSpecifics(const sync_pb::EntitySpecifics& specifics) {
   if (specifics.has_app_notification())
     return APP_NOTIFICATIONS;
 
+  if (specifics.has_history_delete_directive())
+    return HISTORY_DELETE_DIRECTIVES;
+
   if (specifics.has_device_info())
     return DEVICE_INFO;
 
@@ -251,6 +259,13 @@ ModelTypeSet UserTypes() {
   return set;
 }
 
+ModelTypeSet EncryptableUserTypes() {
+  ModelTypeSet encryptable_user_types = UserTypes();
+  // We never encrypt history delete directives.
+  encryptable_user_types.Remove(HISTORY_DELETE_DIRECTIVES);
+  return encryptable_user_types;
+}
+
 ModelTypeSet ControlTypes() {
   ModelTypeSet set;
   for (int i = FIRST_CONTROL_MODEL_TYPE; i <= LAST_CONTROL_MODEL_TYPE; ++i) {
@@ -306,6 +321,8 @@ const char* ModelTypeToString(ModelType model_type) {
       return "Extension settings";
     case APP_NOTIFICATIONS:
       return "App Notifications";
+    case HISTORY_DELETE_DIRECTIVES:
+      return "History Delete Directives";
     case DEVICE_INFO:
       return "Device Info";
     default:
@@ -373,6 +390,8 @@ ModelType ModelTypeFromString(const std::string& model_type_string) {
     return EXTENSION_SETTINGS;
   else if (model_type_string == "App Notifications")
     return APP_NOTIFICATIONS;
+  else if (model_type_string == "History Delete Directives")
+    return HISTORY_DELETE_DIRECTIVES;
   else if (model_type_string == "Device Info")
     return DEVICE_INFO;
   else
@@ -443,6 +462,8 @@ std::string ModelTypeToRootTag(ModelType type) {
       return "google_chrome_extension_settings";
     case APP_NOTIFICATIONS:
       return "google_chrome_app_notifications";
+    case HISTORY_DELETE_DIRECTIVES:
+      return "google_chrome_history_delete_directives";
     case DEVICE_INFO:
       return "google_chrome_device_info";
     default:
@@ -470,6 +491,8 @@ const char kSearchEngineNotificationType[] = "SEARCH_ENGINE";
 const char kSessionNotificationType[] = "SESSION";
 const char kAutofillProfileNotificationType[] = "AUTOFILL_PROFILE";
 const char kAppNotificationNotificationType[] = "APP_NOTIFICATION";
+const char kHistoryDeleteDirectiveNotificationType[] =
+    "HISTORY_DELETE_DIRECTIVE";
 const char kDeviceInfoNotificationType[] = "DEVICE_INFO";
 }  // namespace
 
@@ -521,6 +544,8 @@ bool RealModelTypeToNotificationType(ModelType model_type,
     case APP_NOTIFICATIONS:
       *notification_type = kAppNotificationNotificationType;
       return true;
+    case HISTORY_DELETE_DIRECTIVES:
+      *notification_type = kHistoryDeleteDirectiveNotificationType;
     case DEVICE_INFO:
       *notification_type = kDeviceInfoNotificationType;
       return true;
@@ -578,13 +603,14 @@ bool NotificationTypeToRealModelType(const std::string& notification_type,
   } else if (notification_type == kAppNotificationNotificationType) {
     *model_type = APP_NOTIFICATIONS;
     return true;
+  } else if (notification_type == kHistoryDeleteDirectiveNotificationType) {
+    *model_type = HISTORY_DELETE_DIRECTIVES;
   } else if (notification_type == kDeviceInfoNotificationType) {
     *model_type = DEVICE_INFO;;
     return true;
-  } else {
-    *model_type = UNSPECIFIED;
-    return false;
   }
+  *model_type = UNSPECIFIED;
+  return false;
 }
 
 bool IsRealDataType(ModelType model_type) {