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)

return this.messageHandler.sendWithPromise("GetPageMode", null);
  }
  getViewerPreferences() {
    return this.messageHandler.sendWithPromise("GetViewerPreferences", null);
  }
  getOpenAction() {
    return this.messageHandler.sendWithPromise("GetOpenAction", null);
  }
  getAttachments() {
    return this.messageHandler.sendWithPromise("GetAttachments", null);
  }
  getJavaScript() {
    return this.messageHandler.sendWithPromise("GetJavaScript", null);
  }
  getDocJSActions() {
    return this.messageHandler.sendWithPromise("GetDocJSActions", null);
  }
  getPageJSActions(pageIndex) {
    return this.messageHandler.sendWithPromise("GetPageJSActions", {
      pageIndex,
    });
  }
  getPageXfa(pageIndex) {
    return this.messageHandler.sendWithPromise("GetPageXfa", {
      pageIndex,
    });
  }
  getStructTree(pageIndex) {