standardFaceGlyphs

glyphs, a run of host-font text in spec, each with its outline from the bundled face that stands in for spec's generic family (standardFaceOutline), for a canvas whose host has no face of that family, as a browser has none (#593). The outlines are in units of 1000 to the em, and the advances stay the document's. Null when a glyph that draws something has no outline there, so that the run keeps the host's own text.