Blocking 3rd Party Cookies breaks YouTube Iframes

[linuzzx]

Description

When another website uses an iframe from YouTube and you've blocked 3rd party trackers, you can't subscribe to the channel via the Iframe

Steps to Reproduce

1. Block 3rd Party Trackers
2. go to e.g. https://www.curseforge.com/minecraft/modpacks/fabulously-optimized/
3. click on the youtube avatar
4. try to subscribe

Actual result:

Doesn't work

Expected result:

Should work or maybe an option to allow these

Reproduces how often:

Desktop Brave version:

Brave | 1.26.74 Chromium: 91.0.4472.124 (Offizieller Build) (64-Bit) -- | -- Überarbeitung | 7345a6d1bfcaff81162a957e9b7d52649fe2ac38-refs/branch-heads/4472_114@{#6} Betriebssystem | Windows 10 OS Version 2004 (Build 19041.1052) JavaScript | V8 9.1.269.36

Android Device details:

• Install type (ARM, x86):
• Device type (Phone, Tablet, Phablet):
• Android version:

Version/Channel Information:

• Can you reproduce this issue with the current release?
• yes
• Can you reproduce this issue with the beta channel?
• yes
• Can you reproduce this issue with the nightly channel?
• yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields?
• yes
• Does the issue resolve itself when disabling Brave Rewards?
• nope
• Is the issue reproducible on the latest version of Chrome?
• no

Miscellaneous Information:

[ryanbr]

Something about youtube knowing me by hovering over a video, allowing youtube cookies shows the following image.

By default we blocked this from occurring. Also testing with ES enabled.

cc: @pes10k