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)

AutoPrintRegExp,
  DEFAULT_SCALE_VALUE,
  EventBus,
  getActiveOrFocusedElement,
  isValidRotation,
  isValidScrollMode,
  isValidSpreadMode,
  MAX_SCALE,
  MIN_SCALE,
  noContextMenuHandler,
  normalizeWheelEventDirection,
  parseQueryString,
  ProgressBar,
  RendererType,
  ScrollMode,
  SidebarView,
  SpreadMode,
  TextLayerMode,
} from "./ui_utils.js";
import { AppOptions, OptionKind } from "./app_options.js";
import {
  build,
  createPromiseCapability,
  getDocument,
  getFilenameFromUrl,
  getPdfFilenameFromUrl,
  GlobalWorkerOptions,
  InvalidPDFException,
  isPdfFile,
  LinkTarget,