In order for the description in the HTML <head> to be properly updated by this component, the <meta>
element for the site description (meta[name="description"]) must have the property data-react-helmet="true".
Without this property, another <meta name="description"> element will be created rather than updated in initial
one.
Holds the state for the
ActivePageContextand handles updating the HTML<head>element based on page changes.Automatically registers the given root page info.