Settings: Clean up unused header includes and methods.

Now we are fetching storage data using CookiesTreeModel, some of the
headers and methods are no longer needed.

No functional change.

BUG=835712

Change-Id: I7eef4a97aab128cf2df18c1d4b9e9c5547034173
Reviewed-on: https://chromium-review.googlesource.com/c/1433377
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Maggie Cai <mxcai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625896}
2 files changed