arc: Show custom notification via notification surface

ui/arc/notification/arc_notification_surface_collection.h

Index: ui/arc/notification/arc_notification_surface_collection.h
diff --git a/ui/arc/notification/arc_notification_surface_collection.h b/ui/arc/notification/arc_notification_surface_collection.h
new file mode 100644
index 0000000000000000000000000000000000000000..d5cb3a26ea4cbdeb9ff44e0675ef045f6156a0a4
--- /dev/null
+++ b/ui/arc/notification/arc_notification_surface_collection.h
@@ -0,0 +1,70 @@
+// 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_NOTIFICATION_SURFACE_COLLECTION_H_
+#define UI_ARC_NOTIFICATION_ARC_NOTIFICATION_SURFACE_COLLECTION_H_
+
+#include <map>
+#include <string>
+
+#include "base/macros.h"
+#include "base/observer_list.h"
+#include "components/exo/display_observer.h"
+#include "components/exo/notification_surface.h"
+
+namespace exo {
+class NotificationSurface;
+}
+
+namespace arc {
+
+class ArcNotificationManager;
+
+// Keeps track of NotificationSurface created in exo::Display.
+class ArcNotificationSurfaceCollection
+    : public exo::DisplayObserver,
+      public exo::NotificationSurface::Observer {
+ public:
+  class Observer {
+   public:
+    // Invoked when a notification surface is added.
+    virtual void OnNotificationSurfaceAdded(
+        exo::NotificationSurface* surface) = 0;
+
+   protected:
+    virtual ~Observer() = default;
+  };
+
+  ArcNotificationSurfaceCollection();
+  ~ArcNotificationSurfaceCollection() override;
+
+  exo::NotificationSurface* GetSurface(
+      const std::string& arc_notification_key) const;
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+ private:
+  void AddSurface(exo::NotificationSurface* surface);
+
+  // exo::DisplayObserver
+  void OnNotificationSurfaceCreated(
+      exo::NotificationSurface* surface) override;
+
+  // exo::NotificationSurface::Observer
+  void OnNotificationSurfaceDestroying(
+      exo::NotificationSurface* surface) override;
+
+  using NotificationSurfaceMap =
+      std::map<std::string, exo::NotificationSurface*>;
+  NotificationSurfaceMap notification_surface_map_;
+
+  base::ObserverList<Observer> observers_;
+
+  DISALLOW_COPY_AND_ASSIGN(ArcNotificationSurfaceCollection);
+};
+
+}  // namespace arc
+
+#endif  // UI_ARC_NOTIFICATION_ARC_NOTIFICATION_SURFACE_COLLECTION_H_