gpu difference between chrome and brave

[LaurenWags]

Description

Viz Hit-test Surface Layer is different on Chrome and Brave for the same chromium version.

This has been the case for me for several versions (using macOS), but @kjozwiak sees them as the same on his macOS. I'm currently using High Sierra, he has Mojave.

Steps to Reproduce

1. Open Brave, visit brave://gpu
2. Open Chrome which is using same chromium version as your Brave instance, visit chrome://gpu
3. Compare Viz Hit-test Surface Layer setting.

Actual result:

They differ.
Using C77:

Using C78:

Expected result:

Expected them to be the same.

Reproduces how often:

easily

Brave version (brave://version info)

Brave	0.69.135 Chromium: 77.0.3865.120 (Official Build) (64-bit)
Revision	416d6d8013e9adb6dd33b0c12e7614ff403d1a94-refs/branch-heads/3865@{#884}
OS	macOS Version 10.13.6 (Build 17G5019)

Brave	0.71.94 Chromium: 77.0.3865.90 (Official Build) dev (64-bit)
Revision	58c425ba843df2918d9d4b409331972646c393dd-refs/branch-heads/3865@{#830}
OS	macOS Version 10.13.6 (Build 17G5019)

Brave	0.73.1 Chromium: 78.0.3904.50 (Official Build) nightly (64-bit)
Revision	2accdc52c79976e264cd2694df6db31d1fccd8e8-refs/branch-heads/3904@{#658}
OS	macOS Version 10.13.6 (Build 17G5019)

Version/Channel Information:

• Can you reproduce this issue with the current release? yes 0.69.135, yes 0.70.117
• Can you reproduce this issue with the beta channel? unsure, probably
• Can you reproduce this issue with the dev channel? yes (0.71.94 is my dev version)
• Can you reproduce this issue with the nightly channel? yes (0.73.1 is my nightly version)

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? no

Miscellaneous Information:

cc @bsclifton @kjozwiak

[btlechowski]

Not reproducible on Ubuntu

Brave	0.70.117 Chromium: 78.0.3904.50 (Official Build) (64-bit)
Revision	2accdc52c79976e264cd2694df6db31d1fccd8e8-refs/branch-heads/3904@{#658}
OS	Linux

Brave 0.70.117 and Chrome 78.0.3904.50. Viz Hit-test Surface Layer is disabled in both

[kjozwiak]

Originally when I was comparing 0.70.117 CR: 78.0.3904.50 against Chrome 78.0.3904.50, I received the same results when viewing brave://gpu & chrome://gpu. Example:

However, Google pushed a new CR78 a ~3-4hrs ago and Viz Hit-test Surface Layer are different when comparing 0.70.117 CR: 78.0.3904.50 against Chrome 78.0.3904.63. Example:

Perhaps we're being placed into field trails in Chrome where Viz Hit-test Surface Layer is being enabled? Really wished there was a mapping for the variations in chrome://version.

[GeetaSarvadnya]

The issue is Reproduced in Windows 10 x64 - 0.70.118

[LaurenWags]

@GeetaSarvadnya to confirm, you are comparing Chrome 78 to Brave using Chromium 78, correct?

[mkarolin]

From what I can tell, this feature is still disabled by default in C78. The change to enable it by default is here: https://chromium.googlesource.com/chromium/src/+/55112a03100d6f33ce83a84e9df89db94bcf4356 and has only landed in C79 (https://storage.googleapis.com/chromium-find-releases-static/551.html#55112a03100d6f33ce83a84e9df89db94bcf4356).

I thought that the feature is then enabled in Chrome via experiments, but when I check chrome://flags this particular one is set to Default for me.

There's also this curious tidbit in chrome/test/chromedriver/chrome_launcher.cc:

    // In theory the following switch should have no effects, but its absence
    // would cause VizHitTestSurfaceLayer feature to be enabled on Chromium
    // builds, causing a test failure due to https://crbug.com/996865.
    "force-fieldtrials",

So, I think the feature is properly disabled in our build, but I can't quite tell why it is enabled in Chrome.

[bsclifton]

Good call, @mkarolin - this might be a wontfix 👍 Field trials would explain the different

@GeetaSarvadnya confirmed it was C78 earlier

I'm curious what variations are exposed for you in Chrome 78, @GeetaSarvadnya. You can view those by visiting chrome://version in Chrome. If you see entries there, it's possible one is for VizHitTestSurfaceLayer

[rebron]

Closing out as wontfix. Difference is Chrome has fields trial enabled likely changing these values for some users.