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 (width < measuredWidth && this.isFontSubpixelAAEnabled) {
            const characterScaleX = width / measuredWidth;
            restoreNeeded = true;
            ctx.save();
            ctx.scale(characterScaleX, 1);
            scaledX /= characterScaleX;
          } else if (width !== measuredWidth) {
            scaledX +=
              (((width - measuredWidth) / 2000) * fontSize) / fontSizeScale;
          }
        }
        
        
        if (this.contentVisible && (glyph.isInFont || font.missingFile)) {
          if (simpleFillText && !accent) {
            
            ctx.fillText(character, scaledX, scaledY);
          } else {
            this.paintChar(
              character,
              scaledX,
              scaledY,
              patternTransform,
              resetLineWidthToOne
            );
            if (accent) {
              const scaledAccentX =
                scaledX + (fontSize * accent.offset.x) / fontSizeScale;
              const scaledAccentY =
                scaledY - (fontSize * accent.offset.y) / fontSizeScale;