* Add `no_trace` option to JSTraceable derive
* NoTrace wrapper
* Port some types to no_trace schematics
* Fixing my unsafe mistakes (not tracing traceables)
* Add docs & safety guards for no_trace
Safety guards (trait shenanigans) guarantees safety usage of `no_trace`
* Port canvas_traits to no_trace
* Port servo_media to no_trace
* Port net_traits to no_trace
* Port style to no_trace
* Port webgpu to no_trace
* Port script_traits to no_trace
* Port canvas_traits, devtools_traits, embedder_traits, profile_traits to no_trace
* unrooted_must_root lint in seperate file
* Add trace_in_no_trace_lint as script_plugin
* Composable types in must_not_have_traceable
* Introduced HashMapTracedValues wrapper
* `HashMap<NoTrace<K>,V>`->`HashMapTracedValues<K,V>`
* Port rest of servo's types to no_trace
* Port html5ever, euclid, mime and http to no_trace
* Port remaining externals to no_trace
* Port webxr and Arc<Mutex<_>>
* Fix spelling in notrace doc
Send>
We don't have `window` for `workers`. So, if we use `global.as_window()`
to get the DOMManipulationTaskSource, it will make worker panic.
Instead, we should get the DOMManipulationTaskSource from each own
thread.
Ref: https://github.com/servo/servo/pull/20755#discussion_r193557746
http://www.robohornet.org gives a score of 101.36 on master,
and 102.68 with this PR. The latter is slightly better,
but probably within noise level.
So it looks like this PR does not affect DOM performance.
This is expected since `Box::new` is defined as:
```rust
impl<T> Box<T> {
#[inline(always)]
pub fn new(x: T) -> Box<T> {
box x
}
}
```
With inlining, it should compile to the same as box syntax.
