Add Element.style support for stylo
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This is the Servo side change of [bug 1294299](https://bugzilla.mozilla.org/show_bug.cgi?id=1294299) which has been reviewed by @heycam, @emilio, and @SimonSapin.
This should not be merged until the Gecko side change gets merged into mozilla-central.
r? @heycam
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Stop passing now-unrecognized --no-type-renaming to rust-bindgen.
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r? @emilio
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It is called nsstring_vendor since libgkrust already depends on nsstring, and
we can't have two crates with the same name in-tree. We can't directly depend
on the in-tree one since this will stop independent `./mach build-geckolib` builds from working.
MozReview-Commit-ID: CR4tHgzXWFZ
Run bindings tests with whole crate
We currently run bindgen's autogenerated `#[test]` blocks directly on the structs files.
That is, after generating them, we run `rustc --test` on them. This works fine for now, but
if you want to refer to types defined outside of these files (e.g. in https://bugzilla.mozilla.org/show_bug.cgi?id=1309165),
the tests are broken.
This puts a `cargo test -p style` in `./mach test-stylo`. I disabled doctests because they were failing (unable to find the `ns!()` and `atom!()` macros), and I couldn't figure out why -- will investigate in a later bug.
r? @emilio
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Start simplifying FFI ownership sugar
This is step one of a series of changes planned to make the ownership sugar easier to use. This was blocked on #13038
*very* unsure about second commit. Don't like the thought of accepting types with destructors over FFI. Probably will revert it. Leaving it in for now in case you have some insight.
Eventually at least for the borrowed stuff I want to use T directly (because the crates are merged now), instead of the fake void types. Perhaps for the others too. I might include those changes in this PR -- was originally planning to but I realized that these steps could be split out.
Tentative plan for `Owned` (assuming it's not removed) is to have `Owned<T> <-> Box<T>` (same `T`, no "FFI type") conversions. We will only use ownership wrapper types for things with destructors, and try to keep the conversion simple. I'm envisioning a couple methods for arc/strong and a few more for box/owned. We may need to introduce new wrapper types for gecko-side managed objects (`RefPtr<T>`, `UniquePtr<T>`) but that should be all the wrapper types we have in the ownership sugar.
This PR relies on the guarantee that `Option<&T>` and `Option<Box<T>>` are pointer-sized via the `NonZero` optimization. I am now less unconvinced that this is a good idea 😉.
r? @emilio
cc @mystor
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Move --use-msvc-mangling out from clang flags.
`--use-msvc-mangling` is not a clang flag, but a flag for bindgen.
r? @emilio
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