Made notification center notifications collapsed and expandable.

ui/message_center/notification_change_observer.h

+// Copyright (c) 2013 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_MESSAGE_CENTER_NOTIFICATION_CHANGE_OBSERVER_H_
+#define UI_MESSAGE_CENTER_NOTIFICATION_CHANGE_OBSERVER_H_
+
+#include <string>
+
+#include "ui/gfx/native_widget_types.h"
+
+namespace message_center {
+
+// For classes that need to handle or propagate notification changes.
+class MESSAGE_CENTER_EXPORT NotificationChangeObserver {

[miket_OOO, 2013/03/05 18:41:32]

If you anticipate both that (1) this observer class will be adding more methods
in the future, and (2) the folks doing concrete implementations will be spread
across many different OWNER areas of the codebase, then you might want to
consider default implementations of these methods, so that adding new methods
won't cause a hellish N-reviewer mess across OWNERS.

+ public:
+  virtual ~NotificationChangeObserver() {};
+
+  virtual void OnRemoveNotification(const std::string& id, bool by_user) = 0;
+  virtual void OnRemoveAllNotifications(bool by_user) = 0;
+
+  virtual void OnDisableNotificationsByExtension(const std::string& id) = 0;
+  virtual void OnDisableNotificationsByUrl(const std::string& id) = 0;
+
+  virtual void OnShowNotificationSettings(const std::string& id) = 0;
+  virtual void OnShowNotificationSettingsDialog(gfx::NativeView context) = 0;
+
+  virtual void OnExpanded(const std::string& id) = 0;
+  virtual void OnClicked(const std::string& id) = 0;
+  virtual void OnButtonClicked(const std::string& id, int button_index) = 0;
+};
+
+}  // namespace message_center
+
+#endif // UI_MESSAGE_CENTER_NOTIFICATION_CHANGE_OBSERVER_H_