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)

/**
   * @param {PDFPageViewOptions} options
   */
  constructor(options) {
    const container = options.container;
    const defaultViewport = options.defaultViewport;
    this.id = options.id;
    this.renderingId = "page" + this.id;
    this.pdfPage = null;
    this.pageLabel = null;
    this.rotation = 0;
    this.scale = options.scale || DEFAULT_SCALE;
    this.viewport = defaultViewport;
    this.pdfPageRotate = defaultViewport.rotation;
    this._optionalContentConfigPromise =
      options.optionalContentConfigPromise || null;
    this.hasRestrictedScaling = false;
    this.textLayerMode = Number.isInteger(options.textLayerMode)
      ? options.textLayerMode
      : TextLayerMode.ENABLE;
    this.imageResourcesPath = options.imageResourcesPath || "";
    this.renderInteractiveForms = options.renderInteractiveForms !== false;
    this.useOnlyCssZoom = options.useOnlyCssZoom || false;
    this.maxCanvasPixels = options.maxCanvasPixels || MAX_CANVAS_PIXELS;
    this.eventBus = options.eventBus;
    this.renderingQueue = options.renderingQueue;