DevTools: consistently use Maybe for optional values in the protocol generator.

third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp

Index: third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp
diff --git a/third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp b/third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp
index 66242e658dd78bd4ab561e55b25c924fb07639b1..9dc1272110a6855c5ab9c264e7f2e4db1d4db7a8 100644
--- a/third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp
+++ b/third_party/WebKit/Source/modules/webdatabase/InspectorDatabaseAgent.cpp
@@ -63,7 +63,7 @@ void reportTransactionFailed(ExecuteSQLCallback* requestCallback, SQLError* erro
     OwnPtr<protocol::Database::Error> errorObject = protocol::Database::Error::create()
         .setMessage(error->message())
         .setCode(error->code()).build();
-    requestCallback->sendSuccess(nullptr, nullptr, errorObject.release());
+    requestCallback->sendSuccess(Maybe<protocol::Array<String>>(), Maybe<protocol::Array<RefPtr<JSONValue>>>(), errorObject.release());
 }
 
 class StatementCallback final : public SQLStatementCallback {
@@ -99,7 +99,7 @@ public:
             case SQLValue::NullValue: values->addItem(JSONValue::null()); break;
             }
         }
-        m_requestCallback->sendSuccess(columnNames.release(), values.release(), nullptr);
+        m_requestCallback->sendSuccess(columnNames.release(), values.release(), Maybe<protocol::Database::Error>());
         return true;
     }