Control webrender rollout for Fenix

The graphics team is ready to start rolling out Webrender on specific device models. This experiment aims to reduce the risk and give the ability to monitor the impact of the change.

Experimenter is the source of truth for details and delivery. Changes to Bugzilla are not reflected in Experimenter and will not change delivery configuration.

More information: https://experimenter.services.mozilla.com/experiments/control-webrender-rollout-for-fenix/

https://hg.mozilla.org/mozilla-central/rev/45ed19600a37

Re-opening until Fenix github changes have landed:
https://github.com/mozilla-mobile/fenix/pull/7487

Comment on attachment 9118430 [details]
Bug 1605454 - Use GeckoRuntimeSettings intent extras to avoid API change for webrender fenix experiment.

Beta/Release Uplift Approval Request

• User impact if declined: We won't be able to do a performance measurement on Fenix with/without webrender.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This code only affects geckoview and is disabled unless the product (Fenix/Fennec/...) sets the flag. There is a seperate pullrequest for enabling this branch on Fenix that will be reviewed by QA. The codepath that this enables has been extensively tested before as the code just flips a preference to disable the new rendering engine.
• String changes made/needed:

Comment on attachment 9118430 [details]
Bug 1605454 - Use GeckoRuntimeSettings intent extras to avoid API change for webrender fenix experiment.

Needed for Fenix WebRender experiments. Approved for GV73.

Normal practice is to use tracking flags to track uplifts (with the Target Milestone tracking when a patch hit m-c). Feel free to hold off on resolving the bug until the Fenix patch has landed, though.

https://hg.mozilla.org/releases/mozilla-beta/rev/ca844d3ffffc

Fenix code has landed in https://github.com/mozilla-mobile/fenix/pull/7487.

Control WebRender rollout for Fenix on Pixel 2/3

Fenix Beta 73

We have finished testing the Control webrender rollout for Fenix on Pixel 2/3 experiment.

QA’s recommendation: YELLOW - SHIP IT, CONDITIONALLY

Reasoning:

• We found 1 issue that wasn’t fixed and it seems to be generated by the specific web pages visited that are not respecting the about:config option and are keeping the WebRender ON.

• We are concerned by more of an edge case where trying to re-enable WebRender through ADB command, after it was previously disabled also through ADB, it is not possible.

What needs to be done?

• The aforementioned issues need to be addressed or clarified in order to change the sign-off status to GREEN.

Testing Summary:

• Test Suite

Tested Platforms:

• Android 8.0.0 (Google Pixel 2 and 2XL)

• Android 10.0.0 (Google Pixel 3)

Tested Firefox versions:

• Firefox Preview Beta 73

After discussions held on #slack and emails clarifications offered for the reported issues, we have retested the scenarios in cause, and we provided a GREEN sign-off now.