First step towards deferred library support:
- Parse the “deferred as” import clause.
- Implement p.loadLibrary() which returns a future that
completes when the library is loaded.
- Treat type annotations of deferred types as malformed.
- Throw NoSuchMethodError when calling functions from
unloaded libraries.
- Libraries are still read synchronously, but items in the
library won’t be visible through the deferred prefix until
the future returned by loadLibrary() completes.
Review URL: https://codereview.chromium.org//208323015
git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@34481 260f80e4-7a28-3924-810f-c04153c831b5
hausner@google.com