Dart 2 fix for File.open() (#114)

Fixes https://github.com/flutter/flutter/issues/19578
3 files changed
tree: f9adc9f4431dbd9456dd06532b80a4d37cb8cb87
  1. contrib/
  2. dev/
  3. packages/
  4. .gitignore
  5. .travis.yml
  6. analysis_options.yaml
  7. appveyor.yml