Remove some use of FFI in gecko_string_cache
Now that nsIAtom’s mLength and mString can both be accessed directly on the struct, fewer operations need to call into C++ code.
These functions are not used anymore and can be removed from the Gecko side:
* `Gecko_GetAtomAsUTF16`
* `Gecko_AtomEqualsUTF8IgnoreCase`
* `Gecko_AtomEqualsUTF8` (looks like this one was already unused before this PR)
r? @emilio
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The style candidate cache had regressed a few times (see #12534), and my
intuition is that being able to disable all style sharing with a single rule in
the page is really unfortunate.
This commit redesigns the style sharing cache in order to be a optimistic cache,
but then reject candidates if they match different sibling-affecting selectors
in the page, for example.
So far the numbers have improved, but not so much as I'd wanted (~10%/20% of
non-incremental restyling time in general). The current implementation is really
dumb though (we recompute and re-match a lot of stuff), so we should be able to
optimise it quite a bit.
I have different ideas for improving it (that may or may not work), apart of the
low-hanging fruit like don't re-matching candidates all the time but I have to
measure the real impact.
Also, I need to verify it against try.
This configures the regeneration of atoms as part of the normal generation of
bindings, so it stops being a whole different process.
This also adds a generated file to components/style/generated with a convenience
macro invocation for pseudo-elements, which comes handy in order to avoid
duplication.
Look at nsIAtom.mHash directly rather than call Gecko_HashAtom.
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We hash Gecko-backed atoms pretty often. Using bindgen to access to the stored hash in nsIAtom helps with perf a little.
r? @bholley
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