Transformer plugin for polymer. This will make it possible (one day) to use

Transformer plugin for polymer. This will make it possible (one day) to use
polymer transformers in pub-build and pub-serve by writing:

transformers:
  - polymer:
      entry_points: web/index.html


I say one day because there are still a few pending bugs on the vm and the pub
side of things that need to be resolved before this works.

R=jmesserly@google.com

Committed: https://code.google.com/p/dart/source/detail?r=28942

[Jennifer Messerly, 2013-10-19 01:33:32]

lgtm!

[Siggi Cherem (dart-lang), 2013-10-21 19:22:05]

Committed patchset #1 manually as r28942 (presubmit successful).