[Bug 48835] New: Steam broken after March 26 '20 update to CEF 79.0 (64bit; blank window; spamming gl errors)

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=48835

Bug ID: 48835
           Summary: Steam broken after March 26 '20 update to CEF 79.0
                    (64bit; blank window; spamming gl errors)
           Product: Wine
           Version: 5.3
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 66752
  --> https://bugs.winehq.org/attachment.cgi?id=66752
Steam terminal output; wine 5.5; 64bit

Hello,

Steam is broken in 64bit wineprefixes after March 26 '20 update.

(1) Content area in popups and main window remain blank.

Steam spams the terminal output with various GL errors.
Those errors didn't exists before the update.

(2) Steam also uses nearly 2GB of RAM with 8 steamwebhelper process (100MB ~
250 MB). One of the steamwebhelper process is stuck at 100% cpu usage.

This causes problems in a game (World of Warships).
Game fails when all RAM memory is used and disk swapping begins.
RAM consumption is 1GB idle, 3GB Steam running, and rise to 7.9GB + 500MB disk
swap when game is failing. (System has 8GB RAM).

Issue (1) doesn't affect Steam in 32bit wineprefixes.
Issue (2) is common to Steam in both 32 and 64bit wineprefixes.

The two issues may be related, but this bug is about Issue (1).

--- Steam release patch notes ---
(...)
Updated embedded Chromium build in Steam to 79.0.3945.117
(...)
--- end Steam release patch notes ---

First seen on wine 5.3, update to 5.5 doesn't fix the issue.
wine-staging doesn't fix the issue either.

Regards.