Avoids duplicated code when implementing the CSS properties accessors in
CSSStyleDeclaration WebIDL. Servo internal CSS properties are not
accessible.
CSS property "float" is unnacessible because we currently lack support
for BinaryName IDL annotation (#4435).
Fixes#4429, #4430.
Notes:
* This adds `#![allow(missing_copy_implementations)]` to components/*/lib.rs. I'm not sure how to approach the missing Copy warnings (are there things for which Copy should NOT be implemented, and how can I tell?) so I stuck this in to make life easier when looking through the warnings. I can easily remove this if necessary.
* This leaves the following type of warnings, which I couldn't figure out how to approach (I'll investigate it later if no one else wants to).
```
css/matching.rs:72:23: 72:35 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:72 this_as_query.equiv(other)
^~~~~~~~~~~~
css/matching.rs:95:10: 95:49 warning: use of deprecated item: Use overloaded core::cmp::PartialEq, #[warn(deprecated)] on by default
css/matching.rs:95 impl<'a> Equiv<ApplicableDeclarationsCacheEntry> for ApplicableDeclarationsCacheQuery<'a> {
```
through display list building.
The old `flow_origin` concept was ill-defined (sometimes the border box
plus the flow origin, sometimes including horizontal margins and
sometimes not, sometimes including relative position and sometimes not),
leading to brittleness and test failures. This commit reworks the logic
to always pass border box origins in during display list building.
This does not implement any notion of CSSStyleDeclaration objects that do not have an owning element; there's no actual CSS object model in play here. This does support setting and getting properties of the style attribute for HTMLElement, and tries to implement the ambiguous CSS value serialization spec.
I'm not sure how we want to handle Linux cursors, and GLFW has no
ability to set cursors (short of disabling it and managing it yourself).
If you test this in the wild you will probably hit #4357 until that PR lands.
We can reset `<input type=text>` fields! I wish I could've done something with checkboxes, but unfortunately, that's it for now.
In addition to that, this PR implements `HTMLInputAttribute.defaultValue`, updates wpt-test to expect passing tests as a result of that implementation, and fixes an index error crash with text inputs.
edit: also includes an html example where one may lazily watch form resets in action: ` tests/html/form_reset_handsfree.html`
