2FA via Google prompt not working

[kjozwiak]

Description

Looks like 2FA via Google Prompt has regressed under 0.65.x. Seems like YubiKey is working without any issues but Google Prompt doesn't. Seems like a regression with C74?

• 0.65.17 Chromium: 74.0.3729.40 - Reproduced
• 0.64.35 Chromium: 73.0.3683.75 - Couldn't reproduce
• 0.62.50 Chromium: 73.0.3683.86 - Couldn't reproduce

Steps to Reproduce

You'll need to have Google Prompt set as the default 2FA method

1. login into Gmail using user/name password
2. you'll get a Try again right away

You'll need to click on Try another way and authenticate using another 2FA method.

Actual result:

Expected result:

Should be able to login using Google Prompt as my 2FA method

Reproduces how often:

100% reproducible

Brave version (brave://version info)

Brave	0.65.17 Chromium: 74.0.3729.40 (Official Build) nightly(64-bit)
Revision	278d6a0d856d8314f36fb9a68b6e1d85cd0d14e7-refs/branch-heads/3729@{#470}
OS	Mac OS X

Reproducible on current release:

Couldn't reproduce using 0.62.50, see description for more details.

• Does it reproduce on brave-browser dev/beta builds? Couldn't reproduce, see description for details re: channels.

Website problems only:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Is the issue reproducible on the latest version of Chrome? N/A

Additional Information

CCing @brave/legacy_qa