mash: Place views Wi-Fi network config dialogs in correct window parent

ui/views/widget/widget_parent.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 UI_VIEWS_WIDGET_WIDGET_PARENT_H_
+#define UI_VIEWS_WIDGET_WIDGET_PARENT_H_
+
+#include "ui/gfx/native_widget_types.h"
+
+namespace views {
+
+// Utility struct for storing the parent of a Widget. Most useful on mus where
+// gfx::NativeWindow is not a ui::Window.
+struct WidgetParent {
+  static const int kInvalidContainerId = -1;
+
+  // Used on Windows, Linux and classic ash Chrome OS to specify the parent.
+  // Can be used as a parent under mus if it is a top-level window that has a
+  // corresponding ui::Window.
+  gfx::NativeWindow native_parent = nullptr;
+
+  // Opaque container ID. Interpretation is platform-specific. Commonly used to
+  // store an ash shell window ID in mash.
+  int container_id = kInvalidContainerId;
+
+  // TODO(jamescook): Add display ID.
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WIDGET_WIDGET_PARENT_H_