Shields UX popup slow/fails to load, during+after high memory load

[mcint]

Description

The Brave Shields pop-down fails to load for arbitrary amounts of time / forever, showing only the base thin white box.

I encounter this frequently, but I cannot reliably reproduce.

If I encounter this issue, then close all windows but do not restart the browser, the issue remains when I open up the first (and subsequent) new tabs and windows.

Steps to Reproduce

1. Get Brave into a high memory usage situation. Many YouTube and/or Twitter tabs (dozens) will often do the trick
2. Check that shields still show, if they do not, load more tabs, per step 1.
3. Attempt to open shields. The box may be slow, or may not render beyond the initial small white box.

Actual result:

Expected result:

Shields interface renders for interaction.

Reproduces how often:

I encounter this frequently, but I cannot reliably reproduce.

It seems to be triggered by memory pressure and swapping, but it persists

Brave version (brave://version info)

Brave	1.18.78 Chromium: 87.0.4280.141 (Official Build) (x86_64)
Revision	9f05d1d9ee7483a73e9fe91ddcb8274ebcec9d7f-refs/branch-heads/4280@{#2007}
OS	macOS Version 10.14.6 (Build 18G7016)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Not attempted
• Can you reproduce this issue with the nightly channel? Not attempted

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A, Shields at issue/can't
• Does the issue resolve itself when disabling Brave Rewards? disabled anyway
• Is the issue reproducible on the latest version of Chrome? No, relates to Shields

Miscellaneous Information:

[rebron]

@mcint Are you still encountering this issue with 1.23.71? These types of intermittent issues are difficult to reproduce.

[OzakIOne]

I had the same problem on my profile for quite a while, i had dozens of tabs open and adding / removing more during browsing session, and the brave shield popup was very slow to open (waiting 700ms+ up to 1.5s)

After closing most tabs to be around 3 and then close brave and open it again with those 3 tabs seems to have fixed the problem, now the popup opens instantly, i'll see if the problem occurs again and how / when especially it does, i'll try to update here

Brave version (brave://version info)

Brave	1.33.106 Chromium: 96.0.4664.110 (Official Build) (64-bit)
Revision	d5ef0e8214bc14c9b5bbf69a1515e431394c62a6-refs/branch-heads/4664@{#1283}
OS	Windows 10 Version 21H1 (Build 19043.1348)
JavaScript	V8 9.6.180.21

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Not attempted
• Can you reproduce this issue with the nightly channel? Not attempted

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? N/A
• Does the issue resolve itself when disabling Brave Rewards? No (I have rewards enabled, haven't tried disabling them as the issue is comming from having multiple tabs)
• Is the issue reproducible on the latest version of Chrome? No, relates to Shields