Setup subscriptions to deal with overlapping outline service calls
Added todo and encapsulating the build outline
Removed traces and cleaned up.  Clarified Todo
Moved completer outside of buildOutline() so we can complete it when the build is canceled.
Merge pull request #1504 from dart-lang/umop-outline-html_sync_issue

Setup build for outline so that the one build doesn't show up on another file's outline.