Accepting the name of the event as a `DOMString` means that when events
are constructed from within Servo (for instance via input event
handling), the static strings are converted to an owned `String`
wrapped in a `DOMString` and then finally converted to an `Atom` in
`Event`. This makes it so that all non-generated `Event` constructors
accept `Atom`, which can avoid a conversion entirely when the atom
already exists on the Stylo atoms list and eliminate one in-memory copy
in the case that it isn't on the atom list.
Eventually, all event names can be on the atom list and we can eliminate
all copies. This is a tiny optimization, but also makes the code much
friendlier everywhere.
Testing: This should not change behavior so should be covered by
existing test.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
291e9e57cb