[chromedriver] Allow commands to be async.

chrome/test/chromedriver/alert_commands.cc

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/test/chromedriver/alert_commands.h"
 
+#include "base/callback.h"
 #include "base/values.h"
 #include "chrome/test/chromedriver/chrome/chrome.h"
 #include "chrome/test/chromedriver/chrome/devtools_client.h"
 #include "chrome/test/chromedriver/chrome/javascript_dialog_manager.h"
 #include "chrome/test/chromedriver/chrome/status.h"
 #include "chrome/test/chromedriver/chrome/web_view.h"
 #include "chrome/test/chromedriver/session.h"
 
 Status ExecuteAlertCommand(
      const AlertCommand& alert_command,
@@ skipping 75 matching lines @@
 Status ExecuteDismissAlert(
     Session* session,
     WebView* web_view,
     const base::DictionaryValue& params,
     scoped_ptr<base::Value>* value) {
   Status status = web_view->GetJavaScriptDialogManager()
       ->HandleDialog(false, session->prompt_text.get());
   session->prompt_text.reset();
   return status;
 }