arc: Show custom notification via notification surface

ui/arc/notification/arc_notification_item.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_ARC_NOTIFICATION_ARC_NOTIFICATION_ITEM_H_
 #define UI_ARC_NOTIFICATION_ARC_NOTIFICATION_ITEM_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/arc/notification/arc_notification_manager.h"
+#include "ui/arc/notification/arc_notification_surface_collection.h"
 #include "ui/message_center/message_center.h"
 
 namespace arc {
 
 // The class represents each ARC notification. One instance of this class
 // corresponds to one ARC notification.
-class ArcNotificationItem {
+class ArcNotificationItem : public ArcNotificationSurfaceCollection::Observer {

[yoshiki, 2016/06/15 11:47:20]

Most of ArcNotificationItem code is not shared with custom notification. Could
you create a new class like ArcCurstomNotificationItem which inherits
ArcNotificationItem (or new base class like ArcNotificationItemBase)?

[xiyuan, 2016/06/15 19:32:44]

Done.

  public:
   ArcNotificationItem(ArcNotificationManager* manager,
                       message_center::MessageCenter* message_center,
                       const std::string& notification_key,
                       const AccountId& profile_id);
-  ~ArcNotificationItem();
+  ~ArcNotificationItem() override;
 
   void UpdateWithArcNotificationData(const mojom::ArcNotificationData& data);
 
   // Methods called from ArcNotificationManager:
   void OnClosedFromAndroid(bool by_user);
 
   // Methods called from ArcNotificationItemDelegate:
   void Close(bool by_user);
   void Click();
   void ButtonClick(int button_index);
 
  private:
+  // ArcNotificationSurfaceCollection::Observer
+  void OnNotificationSurfaceAdded(exo::NotificationSurface* surface) override;
+
   void OnImageDecoded(const SkBitmap& bitmap);
 
+  // Add |notification_| to message center and update again if there is
+  // |newer_data_|.
+  void AddToMessageCenter();
+
   ArcNotificationManager* const manager_;
   message_center::MessageCenter* const message_center_;
   const AccountId profile_id_;
 
   const std::string notification_key_;
   const std::string notification_id_;
 
   // Stores on-going notification data during the image decoding.
   // This field will be removed after removing async task of image decoding.
   std::unique_ptr<message_center::Notification> notification_;
@@ skipping 12 matching lines @@
 
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<ArcNotificationItem> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcNotificationItem);
 };
 
 }  // namespace arc
 
 #endif  // UI_ARC_NOTIFICATION_ARC_NOTIFICATION_ITEM_H_