[FEATURE] Type inference to improve command completion proposals

[pq]

(from user-submitted feedback):

Nice and simple, but what disappoints me is this:

var doc = window.document;

I cannot get any intellisence on doc now; there is no type-inference. This means I have to painfully spell out types even in method local variables.
(But besides that; i like the editor. I guess the next step would be an HTML editor with built in support for Dart - as well as a version of Chrome with built in support for Dart for faster prototyping.)

[stevemessick]

Added Started label.

[stevemessick]

Set owner to @stevemessick.

[clayberg]

Issue #855 has been merged into this issue.

[clayberg]

Added this to the M1 milestone.

[stevemessick]

Added Fixed label.