Split cache: fill in the NIK for subresource request from shared worker

Tested by expanding the existing
service_worker_network_isolation_key_browsertest.cc and rename it to
worker_network_isolation_key_browsertest.cc.

Bug: 955476
Change-Id: I8d9dcca983049a870d33175550fbef958ef4054e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1692968
Commit-Queue: Yao Xiao <yaoxia@chromium.org>
Reviewed-by: Shivani Sharma <shivanisha@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676479}
10 files changed