GitLab

This replaces the bits of GetAssertionRequestHandler that request a
PIN/UV Auth Token by calling out to AuthTokenRequester instead. See
CL:2469445 for the equivalent CL for MakeCredential.

Bug: 1139111
Change-Id: I1669258ffabc679a5b6d0592ed14fbdaa710dc3f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2536930Reviewed-by: Nina Satragno <nsatragno@chromium.org>
Commit-Queue: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#829271}