Share style resolvers between author shadow trees without style sheets

[Antti Koivisto]

Just for UA shadow tree resolver for now.

[Antti Koivisto]

Created attachment 427145 [details]
wip

[Antti Koivisto]

Created attachment 427276 [details]
patch

[Antti Koivisto]

Created attachment 427336 [details]
patch

[Antti Koivisto]

Created attachment 427338 [details]
patch

[Sam Weinig]

Comment on attachment 427338 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=427338&action=review

> Source/WebCore/ChangeLog:10
> +        Prepare for sharing style resolvers (and all the related data) between shadow trees beyond
> +        the currently supported user agent shadow trees. This patch refactors the sharing code
> +        and adds support for sharing resolvers for author shadow trees without style sheets.

How (if at all) do we test resolver sharing? Could we add some sort of dumping of the resolver state if we don't have a better way?

> Source/WebCore/style/StyleResolver.h:144
> +    bool wasShared() const { return m_wasShared; }
> +    void setWasShared() { m_wasShared = true; }

If this is really meant to be only for shared between shadow trees (as I think the change log indicates), I think making the name a bit more verbose and/or adding a comment would be good.

> Source/WebCore/style/StyleScope.cpp:537
> +    Vector<RefPtr<CSSStyleSheet>> newStyleSheets;

You could make this slight more efficient using a newStyleSheets.reserveInitialCapacity() here.

> Source/WebCore/style/StyleScope.cpp:539
> +    m_resolver->appendAuthorStyleSheets(newStyleSheets);

Seems like unfortunate refchurn. Can we move  newStyleSheets into appendAuthorStyleSheets (may require making a appendAuthorStyleSheets overload that takes an r-value).

[Antti Koivisto]

> How (if at all) do we test resolver sharing? Could we add some sort of
> dumping of the resolver state if we don't have a better way?

Good point, I'll add some sort of testing thing to Internals.

[Antti Koivisto]

Created attachment 427404 [details]
patch

[Antti Koivisto]

Created attachment 427405 [details]
patch

[Antti Koivisto]

Created attachment 427406 [details]
patch

[Antti Koivisto]

Created attachment 427408 [details]
patch

[EWS]

Committed r276836 (237187@main): <https://commits.webkit.org/237187@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 427408 [details].

[Radar WebKit Bug Importer]

<rdar://problem/77377222>