ServiceWorker: Make the main_script_loader_factory non-associated

The current main_script_loader_factory is defined as associated in
the shared_worker_factory.mojom, which is unnecessary.

This CL makes it to be non-associated.

BUG=949543

Change-Id: Ifdc6311115cd08ef20d7a2cbffe45ccdaf538547
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1578355
Commit-Queue: Minggang Wang <minggang.wang@intel.com>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653919}
17 files changed