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

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

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 45 matching lines @@
 static const char databaseAgentEnabled[] = "databaseAgentEnabled";
 };
 
 namespace {
 
 void reportTransactionFailed(ExecuteSQLCallback* requestCallback, SQLError* error)
 {
     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 {
 public:
     static StatementCallback* create(PassRefPtr<ExecuteSQLCallback> requestCallback)
     {
         return new StatementCallback(requestCallback);
     }
 
     ~StatementCallback() override { }
@@ skipping 15 matching lines @@
         OwnPtr<protocol::Array<RefPtr<JSONValue>>> values = protocol::Array<RefPtr<JSONValue>>::create();
         const Vector<SQLValue>& data = rowList->values();
         for (size_t i = 0; i < data.size(); ++i) {
             const SQLValue& value = rowList->values()[i];
             switch (value.type()) {
             case SQLValue::StringValue: values->addItem(JSONString::create(value.string())); break;
             case SQLValue::NumberValue: values->addItem(JSONBasicValue::create(value.number())); break;
             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;
     }
 
 private:
     StatementCallback(PassRefPtr<ExecuteSQLCallback> requestCallback)
         : m_requestCallback(requestCallback) { }
     RefPtr<ExecuteSQLCallback> m_requestCallback;
 };
 
 class StatementErrorCallback final : public SQLStatementErrorCallback {
@@ skipping 214 matching lines @@
 }
 
 DEFINE_TRACE(InspectorDatabaseAgent)
 {
     visitor->trace(m_page);
     visitor->trace(m_resources);
     InspectorBaseAgent::trace(visitor);
 }
 
 } // namespace blink