WebRenderTextureHostWrapper is used only for video(async ImageHost). It could be also used for canvas(sync ImageHost).

WebRenderTextureHostWrapper::UpdateWebRenderTextureHost() does not use WebRenderAPI::RunOnRenderThread(), it could make frame canvas is rendered one frame early. That was the reason why WebRenderTextureHostWrapper was not used for canvas(sync ImageHost).

attachment 9044105 [details] improved glterrain a lot on windows10-64-qr.

https://treeherder.mozilla.org/perf.html#/compare?originalProject=try&originalRevision=e03381e5acde5900983309887696ad1eff58c95e&newProject=try&newRevision=7b4a1f0ea04d3ecd10cd7f88cf7510b4523f517c&framework=1

https://hg.mozilla.org/mozilla-central/rev/73b8e1b44334

== Change summary for alert #19505 (as of Wed, 20 Feb 2019 07:54:57 GMT) ==

Improvements:

20% glterrain windows10-64-qr opt e10s stylo 0.97 -> 0.78

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=19505

Another improvement from Raptor:

== Change summary for alert #19451 (as of Mon, 18 Feb 2019 13:16:10 GMT) ==

Improvements:

5% raptor-motionmark-animometer-firefox windows10-64-qr opt 41.59 -> 43.52

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=19451

Comment on attachment 9044105 [details]
Bug 1526213 - Enable WebRenderTextureHostWrapper for canvas

Beta/Release Uplift Approval Request

• Feature/Bug causing the regression: None
• User impact if declined: Canvas(WebGL/Canvas2D) performance is not good with WebRender. The patch improved talos glterrain(WebGL test) 20%.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• 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): The patch is relatively simple and basic implementation is already used for video playback long timer.
• String changes made/needed: None

Does this only affect Firefox when WebRender is preffed on?
We're getting close to the 66 release date, so if this can wait till 67, I'd prefer to let it stay in 67.

Yes, it affect only when WebRender is preffed on. Ok, no problem to stay in 67.

Thanks!