Remove deprecated CustomFeedback flow for Android.

It was never launched and there are no plans to ramp it up
past the very, very old experiment.

BUG=913677

Change-Id: I66e22b3f16693a98104dcf56e5bb1dc8ac6fd786
Reviewed-on: https://chromium-review.googlesource.com/c/1372360
Reviewed-by: Jesse Doherty <jwd@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Ted Choc <tedchoc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#616911}
10 files changed