This enum was validated but not implemented.

TEST=RequestExtensionTest.Queries

BUG=890689

Change-Id: I7285e45cef53b197d61cd0dfa9d2bacb70e23e64
Reviewed-on: https://chromium-review.googlesource.com/1255142Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Yuly Novikov <ynovikov@google.com>
Commit-Queue: Geoff Lang <geofflang@chromium.org>