Add git hashes specifying multivm reference builds.

R=kustermann@google.com

Review URL: https://codereview.chromium.org//405363003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38452 260f80e4-7a28-3924-810f-c04153c831b5
- Fail if toolchain is not set instead of warning always even if not necessary.

R=whesse@google.com

Review URL: https://codereview.chromium.org//404333004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38460 260f80e4-7a28-3924-810f-c04153c831b5
Unit tests for correction services helpers.

R=paulberry@google.com
BUG=

Review URL: https://codereview.chromium.org//406943003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@38461 260f80e4-7a28-3924-810f-c04153c831b5