[Sync] Add history delete directive type

sync/protocol/proto_value_conversions_unittest.cc

Index: sync/protocol/proto_value_conversions_unittest.cc
diff --git a/sync/protocol/proto_value_conversions_unittest.cc b/sync/protocol/proto_value_conversions_unittest.cc
index d927d2d03a5b9b517a18446d1aa5adb7eda47f9e..cd41895c1bc981e0e47d9ecfd2f048694e9f17c0 100644
--- a/sync/protocol/proto_value_conversions_unittest.cc
+++ b/sync/protocol/proto_value_conversions_unittest.cc
@@ -142,6 +142,10 @@ TEST_F(ProtoValueConversionsTest, ExtensionSpecificsToValue) {
   TestSpecificsToValue(ExtensionSpecificsToValue);
 }
 
+TEST_F(ProtoValueConversionsTest, HistoryDeleteDirectiveSpecificsToValue) {
+  TestSpecificsToValue(HistoryDeleteDirectiveSpecificsToValue);
+}
+
 TEST_F(ProtoValueConversionsTest, NigoriSpecificsToValue) {
   TestSpecificsToValue(NigoriSpecificsToValue);
 }
@@ -190,6 +194,7 @@ TEST_F(ProtoValueConversionsTest, EntitySpecificsToValue) {
   SET_FIELD(bookmark);
   SET_FIELD(extension);
   SET_FIELD(extension_setting);
+  SET_FIELD(history_delete_directive);
   SET_FIELD(nigori);
   SET_FIELD(password);
   SET_FIELD(device_info);