I was wondering if WebGL is considered stable enough to be enabled by default. It makes some PDFs render much faster and it has been off by default for a while now, so we have had quite some time to test it.

If we decide to enable WebGL by default, we should not forget to update https://github.com/mozilla/pdf.js/blob/master/extensions/chromium/preferences_schema.json#L39 as well.

/cc @yurydelendik 
/cc @Snuffleupagus (because IIRC you were testing WebGL too)

this.paintChar(
                accent.fontChar,
                scaledAccentX,
                scaledAccentY,
                patternTransform,
                resetLineWidthToOne
              );
            }
          }
        }
        let charWidth;
        if (vertical) {
          charWidth = width * widthAdvanceScale - spacing * fontDirection;
        } else {
          charWidth = width * widthAdvanceScale + spacing * fontDirection;
        }
        x += charWidth;
        if (restoreNeeded) {
          ctx.restore();
        }
      }
      if (vertical) {
        current.y -= x;
      } else {
        current.x += x * textHScale;
      }
      ctx.restore();
      return undefined;
    }
    showType3Text(glyphs) {