Implement Non-Closable Notification

ui/message_center/message_center.h

Index: ui/message_center/message_center.h
diff --git a/ui/message_center/message_center.h b/ui/message_center/message_center.h
index 00d9545d63943719116e1715efd82ca7c96c25d9..e10eb2bfe6fb186917e8f1b1608ea0f24bb2ad10 100644
--- a/ui/message_center/message_center.h
+++ b/ui/message_center/message_center.h
@@ -50,6 +50,15 @@ class NotifierSettingsProvider;
 
 class MESSAGE_CENTER_EXPORT MessageCenter {
  public:
+  enum class RemoveType {
+    // Remove all notifications (including invisible ones and unclosable ones).

[dewittj, 2016/02/08 18:02:34]

nit: remove the parenthetical phrase - I think |all| is clear enough.

[yoshiki, 2016/02/09 23:42:25]

Done.

+    ALL,
+    // Remove visible notifications including unclosable ones.
+    VISIBLE,

[dewittj, 2016/02/08 18:02:34]

This flag is only used in a test, why don't we just remove it.

[yoshiki, 2016/02/09 23:42:25]

Removed. Done.

+    // Remove closable notification (doesn't remove invisible ones).
+    CLOSABLE,

[dewittj, 2016/02/08 18:02:34]

These flag names are still confusing.  I don't have a great idea for naming, but
just reading the code where these flags are used I am not sure I would have an
accurate idea of what they actually do without reading the documentation here.

Possibly renaming the "closable" concept would be better.  Something like
"pinned" may convey the idea of keeping them around better?

[yoshiki, 2016/02/09 23:42:25]

Thank you for suggestion! Renamed this to "pinned".

+  };
+
   // Creates the global message center object.
   static void Initialize();
 
@@ -102,8 +111,7 @@ class MESSAGE_CENTER_EXPORT MessageCenter {
 
   // Removes an existing notification.
   virtual void RemoveNotification(const std::string& id, bool by_user) = 0;
-  virtual void RemoveAllNotifications(bool by_user) = 0;
-  virtual void RemoveAllVisibleNotifications(bool by_user) = 0;
+  virtual void RemoveAllNotifications(bool by_user, RemoveType type) = 0;
 
   // Sets the icon image. Icon appears at the top-left of the notification.
   virtual void SetNotificationIcon(const std::string& notification_id,