Support expression evaluation when running

[annagrin]

Expression evaluation in a debugger while running is supported currently on other platforms. Investigate what needs to be done to support it in dwds.

• Dart code allows evaluation in a root library when app is not paused, but dart DevTools does not

  • Suggestions:
    • call vmService.evaluate() on root library ID in DevTools if app is not paused.
    • See dart-code:
      https://github.com/Dart-Code/Dart-Code/blob/aeea8df97ebe3de1c805f7767bd662cb3bc8f895/src/debug/dart_debug_impl.ts#L1576

• dwds does not always give correct root library

  • Add root library to ddc metadata (probably in a new app-level metadata section?)

• Question: is it possible to support general eval while running (ie pick/find a library to evaluate in?)

  • Should be possible in DevTools, would need UI changes (to pick the library).
  • Is it possible to find the library automatically?

VSCode debugging on MacOS

VSCode debugging on chrome