Resizing windows while brave://newtab is active feels janky when Brave News is enabled

[kjozwiak]

Description

When you have brave://newtab as the active tab and have Brave Today enabled, resizing the window will jank a bit compared to resizing without Brave Today enabled.

Steps to Reproduce

1. launch a brave version that has Brave Today enabled
2. make sure that brave://newtab is the active tab
3. start resizing the window

Actual result:

Brave appears janky when resizing windows while brave://newtab is active and Brave Today is enabled.

Expected result:

Brave should have the same performance when resizing windows when Brave Today is not enabled

Reproduces how often:

100% reproducible using the above STR.

Brave version (brave://version info)

Brave | 1.19.13 Chromium: 87.0.4280.60 (Official Build) nightly (x86_64)
-- | --
Revision | 12697cfeb273d7de95cf9b18350d2c457f58224c-refs/branch-heads/4280@{#1352}
OS | macOS Version 10.15.7 (Build 19H2)

Version/Channel Information:

• Can you reproduce this issue with the current release? N/A
• Can you reproduce this issue with the beta channel? N/A
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

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

Miscellaneous Information:

CCing @petemill @bsclifton @rebron

[rebron]

Closing in favor of #12700

[petemill]

12700 is about design / layout. Whereas this issue is about performance / jaggy resize behavior. We should keep this issue open IMO.

[9at8]

Scrolling the brave today feed also feels very janky

[9at8]

I haven't looked into it, but it looks like the brave today spends a lot of time trying to paint. Possibly could be fixed by some CSS magic. :man_shrugging:

[mattmcalister]

Leaving this open. Need to consider it as part of front end UX upgrade work.