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 (ctx.mozCurrentTransform) {
    return;
  }
  ctx._originalSave = ctx.save;
  ctx._originalRestore = ctx.restore;
  ctx._originalRotate = ctx.rotate;
  ctx._originalScale = ctx.scale;
  ctx._originalTranslate = ctx.translate;
  ctx._originalTransform = ctx.transform;
  ctx._originalSetTransform = ctx.setTransform;
  ctx._originalResetTransform = ctx.resetTransform;
  ctx._transformMatrix = ctx._transformMatrix || [1, 0, 0, 1, 0, 0];
  ctx._transformStack = [];
  try {
    
    
    
    const desc = Object.getOwnPropertyDescriptor(
      Object.getPrototypeOf(ctx),
      "lineWidth"
    );
    ctx._setLineWidth = desc.set;
    ctx._getLineWidth = desc.get;
    Object.defineProperty(ctx, "lineWidth", {
      set: function setLineWidth(width) {
        this._setLineWidth(width * LINEWIDTH_SCALE_FACTOR);
      },
      get: function getLineWidth() {