Migrate ServiceWorkerScriptCacheMap methods to net::CompletionOnceCallback

Replace usage of net::CompletionCallback and update callers.

Bug: 807724
Change-Id: I90f180fa481ea20e5e67aaab08f27e421342ca39
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1524045
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#641133}
3 files changed