WebView needs a mechanism to load a web font and create PGFonts from it

In order to be able to implement RT-17428, WebView needs a mechanism to load a web font resource from an InputStream and create PGFonts from that resource.

The requested mechanism is expected to be similar to the FontFactory.registerEmbeddedFont(String name, InputStream stream) method introduced in RT-20169, except for the following differences:
    - The resulting resource should not be registered with any font cache or other registrar so as to let the client (WebView) control the lifetime of the resource. The "name" parameter is therefore not needed.
    - The resulting resource should allow for creation of PGFonts.

The operation that creates a PGFont from a web font resource should accept the "size", "bold", and "italic" parameters that should have the same type and meaning as the respective FontFactory.createFont parameters.

Note that although this issue is classified as a feature, the dependent issue, RT-17428, is actually a bug.