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.
In a later PR, DomRoot<T> will become a type alias of Root<Dom<T>>,
where Root<T> will be able to handle all the things that need to be
rooted that have a stable traceable address that doesn't move for the
whole lifetime of the root. Stay tuned.
`Event` internally stores the `type` as an `Atom`, and we're `String`s
everywhere, which can cause unnecessary allocations to occur since
they'll end up as `Atom`s anyways.
This trait is used to hold onto the downcast and upcast functions of all
castable IDL interfaces. A castable IDL interface is one which either derives
from or is derived by other interfaces.
The deriving relation is represented by implementations of marker trait
DerivedFrom<T: Castable> generated in InheritTypes.
/^[ ]*use dom::bindings::codegen::InheritTypes::.*(Base|Cast|Derived)/ {
/::[a-zA-Z]+(Base|Cast|Derived);/d
s/([{ ])[a-zA-Z]+(Base|Cast|Derived), /\1/g
s/([{ ])[a-zA-Z]+(Base|Cast|Derived), /\1/g
s/, [a-zA-Z]+(Base|Cast|Derived)([},])/\2/g
s/, [a-zA-Z]+(Base|Cast|Derived)([},])/\2/g
/\{([a-zA-Z]+(Base|Cast|Derived))?\};$/d
s/\{([a-zA-Z_]+)\};$/\1;/
}
s/([a-zA-Z]+)Cast::from_ref\(\&?\**([a-zA-Z_]+)(\.r\(\))?\)/\2.upcast::<\1>()/g
s/([a-zA-Z]+)Cast::from_ref\(\&?\**([a-zA-Z_]+)(\.[a-zA-Z_]+\(\))?\)/\2\3.upcast::<\1>()/g
s/\(([a-zA-Z]+)Cast::from_ref\)/\(Castable::upcast::<\1>\)/g
s/([a-zA-Z]+)Cast::from_root/Root::upcast::<\1>/g
s/([a-zA-Z]+)Cast::from_layout_js\(\&([a-zA-Z_.]+)\)/\2.upcast::<\1>()/g
s/([a-zA-Z]+)Cast::to_ref\(\&?\**([a-zA-Z_]+)(\.r\(\))?\)/\2.downcast::<\1>()/g
s/([a-zA-Z]+)Cast::to_ref\(\&?\**([a-zA-Z_]+)(\.[a-zA-Z_]+\(\))?\)/\2\3.downcast::<\1>()/g
s/\(([a-zA-Z]+)Cast::to_ref\)/\(Castable::downcast::<\1>\)/g
s/([a-zA-Z]+)Cast::to_root/Root::downcast::<\1>/g
s/([a-zA-Z]+)Cast::to_layout_js\(&?([a-zA-Z_.]+(\(\))?)\)/\2.downcast::<\1>()/g
s/\.is_document\(\)/.is::<Document>()/g
s/\.is_htmlanchorelement\(\)/.is::<HTMLAnchorElement>()/g
s/\.is_htmlappletelement\(\)/.is::<HTMLAppletElement>()/g
s/\.is_htmlareaelement\(\)/.is::<HTMLAreaElement>()/g
s/\.is_htmlbodyelement\(\)/.is::<HTMLBodyElement>()/g
s/\.is_htmlembedelement\(\)/.is::<HTMLEmbedElement>()/g
s/\.is_htmlfieldsetelement\(\)/.is::<HTMLFieldSetElement>()/g
s/\.is_htmlformelement\(\)/.is::<HTMLFormElement>()/g
s/\.is_htmlframesetelement\(\)/.is::<HTMLFrameSetElement>()/g
s/\.is_htmlhtmlelement\(\)/.is::<HTMLHtmlElement>()/g
s/\.is_htmlimageelement\(\)/.is::<HTMLImageElement>()/g
s/\.is_htmllegendelement\(\)/.is::<HTMLLegendElement>()/g
s/\.is_htmloptgroupelement\(\)/.is::<HTMLOptGroupElement>()/g
s/\.is_htmloptionelement\(\)/.is::<HTMLOptionElement>()/g
s/\.is_htmlscriptelement\(\)/.is::<HTMLScriptElement>()/g
s/\.is_htmltabledatacellelement\(\)/.is::<HTMLTableDataCellElement>()/g
s/\.is_htmltableheadercellelement\(\)/.is::<HTMLTableHeaderCellElement>()/g
s/\.is_htmltablerowelement\(\)/.is::<HTMLTableRowElement>()/g
s/\.is_htmltablesectionelement\(\)/.is::<HTMLTableSectionElement>()/g
s/\.is_htmltitleelement\(\)/.is::<HTMLTitleElement>()/g
