Add the data attribute to the Notification object

Source/modules/notifications/Notification.idl

Index: Source/modules/notifications/Notification.idl
diff --git a/Source/modules/notifications/Notification.idl b/Source/modules/notifications/Notification.idl
index e04824c44f14ba816dad9c88a4619f0699f68f62..a6c6743c643c126d0d0a09ad1792c4e5c3def032 100644
--- a/Source/modules/notifications/Notification.idl
+++ b/Source/modules/notifications/Notification.idl
@@ -56,6 +56,7 @@
     readonly attribute DOMString tag;
     readonly attribute DOMString icon;
     readonly attribute boolean silent;
+    [Custom=Getter] readonly attribute any data;

[Peter Beverloo, 2015/03/10 23:34:26]

Since we haven't send out an Intent to Ship yet, and it will take some time
before we can support this for persistent notifications, you should add a
runtime flag to Source/platform/RuntimeEnabledFeatures.in (with status=testing),
and use a [RuntimeEnabled=] annotation here.

What about "NotificationExperimental" for the name, so that we can re-use it for
future new features?

[Sanghyun Park, 2015/03/11 10:59:52]

I think this name is fine.:)
I'll add this runtime feature flag.

 
     [MeasureAs=NotificationClosed] void close();
 };