Revert of Refactor BeforeInstallPromptEvent to use ScriptPromiseProperty

Source/modules/app_banner/AppBannerCallbacks.cpp

Index: Source/modules/app_banner/AppBannerCallbacks.cpp
diff --git a/Source/modules/app_banner/AppBannerCallbacks.cpp b/Source/modules/app_banner/AppBannerCallbacks.cpp
deleted file mode 100644
index 3da3c29a6dc5eda679dcbf57ec0be562efc53c17..0000000000000000000000000000000000000000
--- a/Source/modules/app_banner/AppBannerCallbacks.cpp
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2015 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 "config.h"
-#include "modules/app_banner/AppBannerCallbacks.h"
-
-namespace blink {
-
-AppBannerCallbacks::AppBannerCallbacks(UserChoiceProperty* userChoice)
-    : m_userChoice(userChoice)
-{
-}
-
-void AppBannerCallbacks::onSuccess(WebAppBannerPromptResult* result)
-{
-    m_userChoice->resolve(AppBannerPromptResult::take(adoptPtr(result)));
-}
-
-} // namespace blink