mash: Introduce ShowWebDialogWithContainer for webui dialogs

chrome/browser/ui/ash/web_dialog_util.h

+// Copyright 2016 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.
+
+#ifndef CHROME_BROWSER_UI_ASH_WEB_DIALOG_UTIL_H_
+#define CHROME_BROWSER_UI_ASH_WEB_DIALOG_UTIL_H_
+
+#include "ui/gfx/native_widget_types.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace ui {
+class WebDialogDelegate;
+}
+
+namespace chrome {
+
+// Creates and shows an HTML dialog with the given delegate and context. The
+// dialog is created as a child of |parent|. If |parent| is null the dialog
+// is placed in a fallback shell window container on the primary display. Either
+// a |parent| or valid |container_id| must be provided. The window is destroyed

[sky, 2016/10/21 23:11:15]

Agaun, document what container_id is. A reference to where to get more
information is fine.

[James Cook, 2016/10/21 23:28:13]

Done.

+// destroyed when it is closed. See also chrome::ShowWebDialog().
+void ShowWebDialogWithContainer(gfx::NativeView parent,
+                                int container_id,
+                                content::BrowserContext* context,
+                                ui::WebDialogDelegate* delegate);
+
+}  // namespace chrome
+
+#endif  // CHROME_BROWSER_UI_ASH_WEB_DIALOG_UTIL_H_