tree 5b3950fe0a2e28e961310cbe0571c6840e874f66
parent e0c18005bab9d7c6a55c5928f33fc92718f9e014
author keertip <keertip@google.com> 1527624615 -0700
committer Alan Knight <alanknight@google.com> 1531512425 -0700

Set default Dart SDK to 2.0.0-dev.56.0.

Also remove unnecessary casts with this SDK upgrade.

tap:https://test.corp.google.com/ui#id=OCL:197670958:BASE:198431238:1527619491777:9000b105

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