GitLab

This CL changes the constructor to take BrowserContext instead of
ServiceWorkerContext. Typically, BrowserContext (Profile) is
readily available in tests, so it makes the test code using the
observer a bit straightforward to read.

Bug: None
Change-Id: Ife88eaf1d82708c9675f6d917b59a51d8777bdd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2432806Reviewed-by: David Bertoni <dbertoni@chromium.org>
Commit-Queue: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810862}