1336041 - Tell if webrender is used to CompositableParentManager::AddCompositable()

Status: RESOLVED DUPLICATE of bug 1337085

(Core :: Graphics: WebRender, defect)

Description

[Sotaro Ikeda [:sotaro]]

It is for Bug 1336021.

If we want to create webrender specific CompositableHost, we need to know if webrender is used in CompositableParentManager::AddCompositable().

Problem is that CompositableParentManager could be ImageBridgeParent. Since Bug 1326421 fix, webrender usage is propagated via widget. But ImageBridgeParent does not stick to widget.

Comment 1

[Sotaro Ikeda [:sotaro]]

Attachment: patch - Tell if webrender is used to CompositableParentManager::AddCompositable()

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8833147 [details] [diff] [review]
patch - Tell if webrender is used to CompositableParentManager::AddCompositable()

Review of attachment 8833147 [details] [diff] [review]:
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This doesn't seem correct. The pref is used to determine whether or not a window should use webrender at the time that the window is created. I don't think we can rely on it here. I'll need to take a look at the lifetime of ImageBridge and who creates it to see what the right way to do this is. I'll do that tomorrow, leaving review flag on me so I don't forget.

Comment 3

[Sotaro Ikeda [:sotaro]]

Thanks!

Comment 4

[Kartikaya Gupta (email:[e-mail])]

I spent some time thinking about this. The option I feel is correct (have the callers of AddCompositable pass in whether or webrender is being used for that compositable) seems to be very involved, because we have to go and annotate a lot of call sites. I'm not sure if it's worth it, I started a discussion [1] on the dev-tech-gfx list to get feedback from others.

[1] https://groups.google.com/d/msg/mozilla.dev.tech.gfx/31oJLl8ic10/Pk7lspysDQAJ

Comment 5

[Kartikaya Gupta (email:[e-mail])]

Comment on attachment 8833147 [details] [diff] [review]
patch - Tell if webrender is used to CompositableParentManager::AddCompositable()

Review of attachment 8833147 [details] [diff] [review]:
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So with bug 1337085 you probably don't even need this patch. The place that will use |aUseWebRender| inside CompositableHost::Create can just use gfxVars::UseWebRender() instead of |aUseWebRender| and so you don't need to propagate the variable around.