[api] remove old deprecated APIs.

These APIs have been marked as deprecated for more than 6 months.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I4f05a8904c367f335be7e159709f564362c8bbd9
Reviewed-on: https://chromium-review.googlesource.com/848782Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50368}