Document Pattern.matchAsPrefix return values.

BUG= http://dartbug.com/21511
R=wibling@google.com

Review URL: https://codereview.chromium.org//699413003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41596 260f80e4-7a28-3924-810f-c04153c831b5
API for producing runnable output from incremental compiler.

R=johnniwinther@google.com

Review URL: https://codereview.chromium.org//701803003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41597 260f80e4-7a28-3924-810f-c04153c831b5
Update import to new location.

Review URL: https://codereview.chromium.org//710633002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41598 260f80e4-7a28-3924-810f-c04153c831b5