Right now the cache can't handle caching the missing glyph.
Created attachment 16689 [details] patch to cache missing glyphs too
Comment on attachment 16689 [details] patch to cache missing glyphs too + glyphRecord = (ATSLayoutRecord *)((char *)glyphRecord + wkGetGlyphVectorRecordSize(glyphVector)); Looks like this was copied from Mac by mistake.
Created attachment 16690 [details] patch to cache missing glyphs too (Windows fixed now)
Comment on attachment 16690 [details] patch to cache missing glyphs too (Windows fixed now) r=me
Committed revision 26696.