[glyf] Fix slant-scaling in GlyphHeader too

src/OT/glyf/GlyphHeader.hh

@@ -21,10 +21,12 @@ struct GlyphHeader
     /* extents->x_bearing = hb_min (glyph_header.xMin, glyph_header.xMax); */
     int lsb = hb_min (xMin, xMax);
     (void) glyf_accelerator.hmtx->get_leading_bearing_without_var_unscaled (gid, &lsb);
-    extents->x_bearing = font->em_scale_x (lsb);
-    extents->y_bearing = font->em_scale_y (hb_max (yMin, yMax));
-    extents->width     = font->em_scale_x (hb_max (xMin, xMax) - hb_min (xMin, xMax));
-    extents->height    = font->em_scale_y (hb_min (yMin, yMax) - hb_max (yMin, yMax));
+    extents->x_bearing = lsb;
+    extents->y_bearing = hb_max (yMin, yMax);
+    extents->width     = hb_max (xMin, xMax) - hb_min (xMin, xMax);
+    extents->height    = hb_min (yMin, yMax) - hb_max (yMin, yMax);
+
+    font->scale_glyph_extents (extents);
 
     return true;
   }