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)

if (fontDirection > 0) {
        ctx.scale(textHScale, -1);
      } else {
        ctx.scale(textHScale, 1);
      }
      let lineWidth = current.lineWidth;
      let resetLineWidthToOne = false;
      const scale = current.textMatrixScale;
      if (scale === 0 || lineWidth === 0) {
        const fillStrokeMode =
          current.textRenderingMode & TextRenderingMode.FILL_STROKE_MASK;
        if (
          fillStrokeMode === TextRenderingMode.STROKE ||
          fillStrokeMode === TextRenderingMode.FILL_STROKE
        ) {
          this._cachedGetSinglePixelWidth = null;
          lineWidth = this.getSinglePixelWidth();
          resetLineWidthToOne = lineWidth < 0;
        }
      } else {
        lineWidth /= scale;
      }
      if (fontSizeScale !== 1.0) {
        ctx.scale(fontSizeScale, fontSizeScale);
        lineWidth /= fontSizeScale;
      }
      ctx.lineWidth = lineWidth;
      let x = 0,
        i;
      for (i = 0; i < glyphsLength; ++i) {