Extract a minimal subset of WebDialogUI/WebDialogDelegate from src/chrome -> src/ui/web_dialogs

chrome/browser/ui/webui/external_web_dialog_ui.cc

+// Copyright (c) 2012 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/browser/ui/webui/external_web_dialog_ui.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/lazy_instance.h"
+#include "base/property_bag.h"
+#include "base/values.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/render_view_host.h"
+#include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_ui.h"
+#include "content/public/browser/web_ui_message_handler.h"
+#include "content/public/common/bindings_policy.h"
+
+
+ExternalWebDialogUI::ExternalWebDialogUI(content::WebUI* web_ui)
+    : web_dialogs::WebDialogUI(web_ui) {
+  // Non-file based UI needs to not have access to the Web UI bindings
+  // for security reasons. The code hosting the dialog should provide
+  // dialog specific functionality through other bindings and methods
+  // that are scoped in duration to the dialogs existence.
+  web_ui->SetBindings(web_ui->GetBindings() & ~content::BINDINGS_POLICY_WEB_UI);
+}
+
+ExternalWebDialogUI::~ExternalWebDialogUI() {
+}