Remove SWWriteToCacheJob and SWRequestHandler::MaybeCreateJob()

They are not used after the launch of S13nServiceWorker.

Bug: 926114,939237
Change-Id: I1378fee341ca4b67029ca2069e9b00384152208e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1522056
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640763}
19 files changed