service worker: Cleanup ServiceWorkerContext

Various cleanup:
* Declare functions in a more sensible order.
* Make definitions match declaration order.
* Add "// static" tag, explicit, other niceties.

Change-Id: I211ac815f9be257462f6bef9e5b788a51650092a
Reviewed-on: https://chromium-review.googlesource.com/651451
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#499936}
4 files changed