Remove RandomForest in favor of ExtraTrees.

Since ExtraTrees seem to be more useful than RandomForest for
our application, remove RF in favor of them.

Change-Id: Ia7301725aa55032bc7fded74139cf143f76f82f2
Reviewed-on: https://chromium-review.googlesource.com/c/1407605
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Commit-Queue: Frank Liberato <liberato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622159}
7 files changed