GWT: expression evaluation of Overlay types in debugger fails

```
Original details are here:

http://code.google.com/p/google-web-toolkit/issues/detail?id=2912

To get the evaluation of overlay types working in the debug view, a patch to 
JDT is needed.

This patch has been written, but it needs to be pushed into JDT core.
```

Original issue reported on code.google.com by `rdayal@google.com` on 2 Jan 2013 at 10:10
