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.preferences = this.externalServices.createPreferences();
    this.appConfig = appConfig;
    await this._readPreferences();
    await this._parseHashParameters();
    this._forceCssTheme();
    await this._initializeL10n();
    if (
      this.isViewerEmbedded &&
      AppOptions.get("externalLinkTarget") === LinkTarget.NONE
    ) {
      
      
      AppOptions.set("externalLinkTarget", LinkTarget.TOP);
    }
    await this._initializeViewerComponents();
    
    
    this.bindEvents();
    this.bindWindowEvents();
    
    const appContainer = appConfig.appContainer || document.documentElement;
    this.l10n.translate(appContainer).then(() => {