fido: disable Touch ID for makeCredential with AuthenticatorAttachment::kAny

This disables platform authenticators (i.e. Touch ID) for makeCredential
requests with an unset AuthenticatorAttachment value in
AuthenticatorSelectionCriteria. This is done to prevent Touch ID
fingerprint prompts for requests that could be handled by external
authenticators, as long as Touch ID is not integrated with UI.

Filed crbug.com/873710 to track reversal of this change once UI
integration is there.

Bug: 678128
Change-Id: I7aaffe53dfca7ee14b5a94f9ead2027ab370c35c
Reviewed-on: https://chromium-review.googlesource.com/1172912
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Reviewed-by: Balazs Engedy <engedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#583020}
4 files changed