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.current.leading = -leading;
    }
    setFont(fontRefName, size) {
      const fontObj = this.commonObjs.get(fontRefName);
      const current = this.current;
      if (!fontObj) {
        throw new Error(`Can't find font for ${fontRefName}`);
      }
      current.fontMatrix = fontObj.fontMatrix || FONT_IDENTITY_MATRIX;
      
      
      if (current.fontMatrix[0] === 0 || current.fontMatrix[3] === 0) {
        warn("Invalid font matrix for font " + fontRefName);
      }
      
      
      if (size < 0) {
        size = -size;
        current.fontDirection = -1;
      } else {
        current.fontDirection = 1;
      }
      this.current.font = fontObj;
      this.current.fontSize = size;
      if (fontObj.isType3Font) {
        return; 
      }
      const name = fontObj.loadedName || "sans-serif";
      let bold = "normal";
      if (fontObj.black) {