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)

waitOn.push(page._destroy());
      }
    }
    this.pageCache.length = 0;
    this.pagePromises.length = 0;
    
    if (this.hasOwnProperty("annotationStorage")) {
      this.annotationStorage.resetModified();
    }
    
    const terminated = this.messageHandler.sendWithPromise("Terminate", null);
    waitOn.push(terminated);
    Promise.all(waitOn).then(() => {
      this.commonObjs.clear();
      this.fontLoader.clear();
      this._hasJSActionsPromise = null;
      if (this._networkStream) {
        this._networkStream.cancelAllRequests(
          new AbortException("Worker was terminated.")
        );
      }
      if (this.messageHandler) {
        this.messageHandler.destroy();
        this.messageHandler = null;
      }
      this.destroyCapability.resolve();
    }, this.destroyCapability.reject);
    return this.destroyCapability.promise;
  }
  setupMessageHandler() {