GitLab

TabFavicon is Tab userdata that provides API for the active
web contents' favicon. This was a part of Tab class but
factored out into its own class.

Bug: 877878, 925242
Change-Id: I49eba08918a2a86985f2b8aea5d4c7e15d666108
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1482434
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637993}