Duplicate switch case value in dart:html

[johnniwinther]

Trying to enable the full exhaustiveness checking flags an "unreachable switch case" warning in dart:html:

output: org-dartlang-sdk:///lib/html/dart2js/html_dart2js.dart:38294:7: Warning: This case is covered by the previous cases.
      case KeyCode.WIN_KEY_LEFT:
      ^

The underlying problem is that KeyCode.WIN_KEY_LEFT and KeyCode.META have the same integer value and the case of KeyCode.META occurs before the case for KeyCode.WIN_KEY_LEFT.

[johnniwinther]

cc @sigmundch

[nshahan]

cc @srujzs

[srujzs]

Seems like the duplicate value was intentional based on https://github.com/google/closure-library/blob/master/closure/goog/events/keycodes.js. Key codes in general are deprecated, so not sure what the status of this code's correctness is. Since META == WIN_KEY_LEFT, I think the right answer is just to remove the second case since it never triggers. https://dart-review.googlesource.com/c/sdk/+/290702