<AWT Dev> [8] Review Request: 8027913 drop target notifications are sent out of order during DnD

[Sergey Bylokhov]

Hello.
Please review the fix for jdk 8.
The problem was in the missing notification about exit drop target 
event. This happens because usual mouse events and SDT events use the 
same fields to track current  / previous component.
In the fix these fields were split.

Bug: https://bugs.openjdk.java.net/browse/JDK-8027913
Webrev can be found at: http://cr.openjdk.java.net/~serb/8027913/webrev.00

-- 
Best regards, Sergey.