service worker: Add UseCounter for FetchEvent#isReload

This feature is at-risk and we need to measure usage.

This patch also fixes a bug where use counter for a page wasn't updated for
features used by the service worker during the main resource load.

Bug: 652994,737355
Change-Id: Ib62e6c3ea4d1f39345a978c6c8c6c752fc1bd022
Reviewed-on: https://chromium-review.googlesource.com/549539
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#482935}
10 files changed