tab hover cards with C91

[LaurenWags]

Description

Noticed on Nightly with C91 version that I have tab hover cards again.

I think Windows on current release has these, but macOS does not.

@rebron also noted that the flag present on C90 builds (brave://flags/#tab-hover-cards) is not available on C91 builds.

Steps to Reproduce

1. Clean profile 1.26.18 (or C91 version)
2. Hover over tab
3. See hover card like below

Actual result:

Expected result:

no hover card

Reproduces how often:

100%

Brave version (brave://version info)

Brave | 1.26.18 Chromium: 91.0.4472.38 (Official Build) nightly (x86_64)
-- | --
Revision | 8155e7afab5d695cf0e028f4d77203287523cda9-refs/branch-heads/4472_35@{#6}
OS | macOS Version 10.15.7 (Build 19H1030)

Version/Channel Information:

• Can you reproduce this issue with the current release? no
• Can you reproduce this issue with the beta channel? no
• Can you reproduce this issue with the nightly channel? yes

Other Additional Information:

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

Miscellaneous Information:

cc @rebron @brave/legacy_qa

[bsclifton]

Let's keep these in place - @rebron has suggested maybe capturing a setting where folks can turn this off. We have that captured with #9906

[ask1234560]

Hello, i am facing the same issue.
The version is 1.25.68 Chromium: 91.0.4472.77 (Official Build) (64-bit)
Distro Arch linux
I had disabled the following flags also.

omnibox-refined-focus-state
tab-hover-card-images

No effect, how to solve the issue.

[bsclifton]

@ask1234560 can you please subscribe to #9906 for updates? You can leave a comment there too. Thanks! 😄