Hello webkit-dev,

I'd like to solicit feedback as well as an official position from Webkit on
our proposal for the new memory measurement API:
https://github.com/WICG/performance-measure-memory

The proposal generalizes the previous performance-memory proposal [1] that was abandoned [2] due to information leak of cross-origin resources. The new API addresses the information leak and process model issues raised in the previous feedback [3].

What is different in the new API?

- It relies on COOP+COEP [4] for preventing cross-origin information leaks (see "Security Considerations"). Besides security, COOP+COEP also helps implementability because the browser needs to isolate the web page from other web pages.

- It does not assume any particular process model and is defined using the standard concepts such as JS agent cluster and browsing context group.

- It has an extensible and generic interface for breaking down memory usage by type (JS, DOM, GPU) and owner. Implementers can choose the level of detail they are willing to provide based on their performance trade-offs (see "Performance Considerations").

Thank you,
Ulan.

[1]: The previous proposal: https://github.com/WICG/performance-memory/blob/master/explainer.md
[2]: Information leak affecting the previous proposal: https://github.com/mozilla/standards-positions/issues/85#issuecomment-426382208
[3]: Feedback from Apple on the previous proposal:
https://github.com/WICG/performance-memory/issues/14
[4]: COOP and COEP explained: https://docs.google.com/document/d/1zDlfvfTJ_9e8Jdc8ehuV4zMEu9ySMCiTGMS9y0GU92k/edit

Other Relevant Links

Explainer: https://github.com/WICG/performance-measure-memory

Open issues: https://github.com/WICG/performance-measure-memory/issues
WebPerf WG F2F June 2019 presentation (for older iteration of the API):
https://docs.google.com/document/d/1uQ7pXwuBv-1jitYou7TALJxV0tllXLxTyEjA2n1mSzY/edit#heading=h.x0ih8vnl6qwo
TAG design review (for older iteration of the API): https://github.com/w3ctag/design-reviews/issues/386
Issue on Mozilla standards-positions: https://github.com/mozilla/standards-positions/issues/281