arc: Show custom notification via notification surface

ui/arc/notification/arc_custom_notification_item.h

Index: ui/arc/notification/arc_custom_notification_item.h
diff --git a/ui/arc/notification/arc_custom_notification_item.h b/ui/arc/notification/arc_custom_notification_item.h
new file mode 100644
index 0000000000000000000000000000000000000000..573fed1ff643f231feec893eba203ca8c69d3292
--- /dev/null
+++ b/ui/arc/notification/arc_custom_notification_item.h
@@ -0,0 +1,41 @@
+// 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_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_ITEM_H_
+#define UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_ITEM_H_
+
+#include "base/macros.h"
+#include "components/exo/notification_surface_registry.h"
+#include "ui/arc/notification/arc_notification_item.h"
+
+namespace arc {
+
+class ArcCustomNotificationItem
+    : public ArcNotificationItem,
+      public exo::NotificationSurfaceRegistry::Observer {
+ public:
+  ArcCustomNotificationItem(ArcNotificationManager* manager,
+                            message_center::MessageCenter* message_center,
+                            const std::string& notification_key,
+                            const AccountId& profile_id);
+  ~ArcCustomNotificationItem() override;
+
+  // TODO(xiyuan): Find a better way to expose NotificationSurfaceRegistry.
+  static void SetNotificationSurfaceRegistry(
+      exo::NotificationSurfaceRegistry* registry);
+
+  void UpdateWithArcNotificationData(
+      const mojom::ArcNotificationData& data) override;
+
+ private:
+  // NotificationSurfaceRegistry::Observer
+  void OnNotificationSurfaceAdded(exo::NotificationSurface* surface) override;
+  void OnNotificationSurfaceRemoved(exo::NotificationSurface* surface) override;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcCustomNotificationItem);
+};
+
+}  // namespace arc
+
+#endif  // UI_ARC_NOTIFICATION_ARC_CUSTOM_NOTIFICATION_ITEM_H_