Switch top-level classic worker fetch to use outsideSettings ResourceFetcher

This CL
- Makes ThreadableLoader and WorkerClassicScriptLoader
  accept a ResourceFetcher argument, and
- Creates and passes outsideSettings in
  WorkerGlobalScope::ImportClassicScriptPausable().

This switches FetchClientSettingsObject used for off-the-main-thread
classic worker top-level script fetch, and fixes
virtual/omt-worker-fetch/external/wpt/referrer-policy
test failures.

Bug: 880027, 835717
Change-Id: I68b6c8025c88362b507fcf84e56571d0e7eea409
Reviewed-on: https://chromium-review.googlesource.com/c/1328565
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#613867}
9 files changed