Check publickey security requirements for calls to get(publicKey)
and handle empty or missing rpIds.

Add layout tests for various combinations of origins and rpId to
get(publicKey) just like the existing ones for create(publicKey).

Bug: 807774, 664630
Change-Id: I86d3d36c3f3825743f003da69245c74bdca10d5b
Reviewed-on: https://chromium-review.googlesource.com/896384
Commit-Queue: Kim Paulhamus <kpaulhamus@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537594}
17 files changed