dart:html missing cleaned up IndexedDB

[sethladd]

dart:html cleans up the DOM, and it's missing a cleaned up version of IndexedDB.

For example, I can't yet do this:

var idb = window.indexedDB; // should handle vendor prefixes and detection for me
var req = idb.open('todo');
req.on.success.add((e) => db = req.result); // should be able to use our fancy events

[sethladd]

Changed the title to: "dart:html missing cleaned up IndexedDB".

[sethladd]

Set owner to @rakudrama.

[rakudrama]

Removed Area-UI label.
Added Area-DOM label.

[rakudrama]

Marked this as blocking #1310.

[vsmenon]

Added Fixed label.