Generate atom files at build-time
The commits here basically do the following things:
1. move all generated files for gecko into "gecko/generated" so that we can copy all of them around
2. make regen_atoms.py generate file to the out dir rather than in-tree
3. make the build script invoke regen_atoms.py when bindgen feature is enabled
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Fix parsing behavior of text-shadow property
Blur radius should reject negative values. There was already `Shadow` struct for properties like this. `filter: drop-shadow` also has the same syntax with that property. I thought sharing the same code would be better and used Shadow struct for parsing. Converted to SpecifiedTextShadow to get rid of unneccessary fields and to be able to convert its computed value. Maybe it would be better to avoid using `Shadow` or just using `Shadow` but sharing code and avoiding unneccessary fields seems better.
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Make stylo support moz-prefixed cursor values.
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This issue is reported at https://bugzilla.mozilla.org/show_bug.cgi?id=1356072.
We need to support the following moz-prefix properties in stylo:
- -moz-grab
- -moz-grabbing
- -moz-zoom-in
- -moz-zoom-out
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- [X] These changes fix [Bug 1356072](https://bugzilla.mozilla.org/show_bug.cgi?id=1356072).
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- [X] These changes do not require tests because the tests already exist in Gecko.
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This part includes making stroke-linecap, stroke-linejoin, stroke-miterlimit,
stroke-opacity, and stroke-dasharray animatable.
For properties that already implemented Interpolate trait and clone() for
glue code, we can just make them animatable by replacing the animation_value_type
with proper type name. So, set animation_value_type to 'discrete' for
stroke-linecap and stroke-linejoin. Set animation_value_type to 'ComputedValue'
for stroke-miterlimit and stroke-opacity.
As to stroke-dasharray, we need to implement Interpolate trait and glue codes
for it.
Stylo: Implement {specified|computed}::LayerImage.
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Bug 1359787 - Stylo: Unite the implementation of background-image/ mask-image and border-image-source in {background|svg|border}.mako.rs
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- [ ] These changes fix #__ (github issue number if applicable).
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