The Constellation
itself. In the servo browser, there is one
constellation, which maintains all of the browser global data.
In embedded applications, there may be more than one constellation,
which are independent of each other.
A logger directed at the constellation from the compositor
A logger directed at the constellation from content processes
#[derive(Clone)]
State needed to construct a constellation.
Creating a new pipeline may require creating a new event loop.
This is the data used to initialize the event loop.
TODO: simplify this, and unify it with InitialPipelineState
if possible.