AllowedByNoSniff cleanup following WorkerNosniff(Block|Warn) removal

 - There is no way to show a warning, so remove the parameter.
 - The decision on mime-type check on worker has been made, so remove
   the use counters. As a result, we can remove
   |is_worker_global_scope| param.

Bug: 794548, 924024
Change-Id: I4a693a7e2d332b2a2ec14aa2f2c060b811f0e68c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1609027
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659434}
8 files changed