Chris Bracken 6e37e9cd8f Check for dart2js on felt startup (flutter/engine#21046) ...

This adds a check for the presence of dart2js in the engine build.

Felt relies on an engine build with `--full-dart-sdk` set. Previously,
we checked for the presence of pub, but not for the presence of
web-specific tooling such as dart2js that felt relies on. Pub is built
as part of the default Dart SDK build when `--full-dart-sdk` is not set,
so its presence is insufficient to prove that other required tooling is
present.

Without this check, we get the following error on run:

    Unhandled exception:
    ProcessException: No such file or directory
      Command: /Users/cbracken/src/flutter/engine/src/out/host_debug_unopt/dart-sdk/bin/dart2js --no-minify --disable-inlining --enable-asserts --enable-experiment=non-nullable --no-sound-null-safety -O2 -o test/paragraph_builder_test.dart.browser_test.dart.js test/paragraph_builder_test.dart

2020-09-09 14:04:52 -07:00

..

src/flutter

Check for dart2js on felt startup (flutter/engine#21046)

2020-09-09 14:04:52 -07:00