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)

const obj = this._ensureObj(objId);
    obj.resolved = true;
    obj.data = data;
    obj.capability.resolve(data);
  }
  clear() {
    this._objs = Object.create(null);
  }
}
/**
 * Allows controlling of the rendering tasks.
 */
class RenderTask {
  constructor(internalRenderTask) {
    this._internalRenderTask = internalRenderTask;
    /**
     * Callback for incremental rendering -- a function that will be called
     * each time the rendering is paused.  To continue rendering call the
     * function that is the first argument to the callback.
     * @type {function}
     */
    this.onContinue = null;
  }
  /**
   * Promise for rendering task completion.
   * @type {Promise<void>}
   */
  get promise() {