Do not call EnsureFetcher() in ThreadableLoader for outsideSettings fetch

Currently, ThreadableLoader always calls EnsureFetcher(),
which is not necessary and
would cause assertion failures when switching the worker's URL
because this creates worker's insideSettings ResourceFetcher
(which depends on ExecutionContext and its URL)
at the start of outsideSettings top-level script fetch.

This CL skips such unnecessary EnsureFetcher() calls and thus
avoids the assertion failures.

Bug: 880027, 835717, 861564
Change-Id: I7768b0274bdc47e856df2a4a529d4b223d978c80
Reviewed-on: https://chromium-review.googlesource.com/c/1394643
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621863}
1 file changed