Add UKMs for Service Worker Static Routing API of Main Resources

This CL adds UKMs for Service Worker Static Routing API of Main
Resources as well as relevant metric hooks.


UKM collection review doc:
https://docs.google.com/document/d/150dNop9dS2NOLRXTDYqD4Rg4kwzZy1uIKGyEyjHoI98

Change-Id: I08dcb2c7bd1e90a3a173aee449a4b4d72ef6044f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5446111
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Shunya Shishido <sisidovski@chromium.org>
Reviewed-by: Minoru Chikamune <chikamune@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Keita Suzuki <suzukikeita@chromium.org>
Reviewed-by: Kouhei Ueno <kouhei@chromium.org>
Reviewed-by: Yoshisato Yanagisawa <yyanagisawa@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1297314}