ServiceWorker: Move frame_tree_node_id etc to ServiceWorkerContainerHost

This is a part of the effort to split ServiceWorkerProviderHost into
ServiceWorkerHost and ServiceWorkerContainerHost.

This CL moves |frame_tree_node_id_|, |fetch_request_window_id_|, and
|web_contents_getter| from ServiceWorkerProviderHost to
ServiceWorkerContainerHost.

Design doc:
https://docs.google.com/document/d/1epWIgelE-7uwxJHrYPKlbwqMRP9in2xLUR6mpiU_afY/edit?usp=sharing

Bug: 931087
Change-Id: Ia95c3dbc70d3e8d55727dfbb65905beb674ca3ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1930366
Commit-Queue: Hiroki Nakagawa <nhiroki@chromium.org>
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718520}
8 files changed