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.linkService.cachePageRef(pageNum, pdfPage.ref);
                if (--getPagesLeft === 0) {
                  this._pagesCapability.resolve();
                }
              },
              reason => {
                console.error(
                  `Unable to get page ${pageNum} to initialize viewer`,
                  reason
                );
                if (--getPagesLeft === 0) {
                  this._pagesCapability.resolve();
                }
              }
            );
          }
        });
        this.eventBus.dispatch("pagesinit", { source: this });
        if (this.defaultRenderingQueue) {
          this.update();
        }
      })
      .catch(reason => {
        console.error("Unable to initialize viewer", reason);
      });
  }
  /**
   * @param {Array|null} labels
   */
  setPageLabels(labels) {