GitLab

- Merge back_forward_cache into navigation folder.
- Move scheduling-related histograms from other to scheduler/.
- Add myself as owner for scheduler/ and navigation/.

R=sweilun@chromium.org,isherman@chromium.org

Change-Id: I6b4d296be8316d65fd6e7da1371f986fcf2fe706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2503730Reviewed-by: Ilya Sherman <isherman@chromium.org>
Commit-Queue: Alexander Timin <altimin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821899}