Delete BrowserSessionContentUtils

It was kept to keep downstream intact, now can be deleted

Bug: 916542
Change-Id: I400c2dec8f4d9eba053e85701f4eb726c97107e9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1718964
Auto-Submit: Pavel Shmakov <pshmakov@chromium.org>
Commit-Queue: Peter Conn <peconn@chromium.org>
Reviewed-by: Peter Conn <peconn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681313}
2 files changed