function VRDisplay() {
  this.isPolyfilled = true;
  this.displayId = nextDisplayId++;
  this.displayName = 'webvr-polyfill displayName';

  this.depthNear = 0.01;
  this.depthFar = 10000.0;

  this.isConnected = true;
  this.isPresenting = false;
  this.capabilities = {
    hasPosition: false,
    hasOrientation: false,
    hasExternalDisplay: false,
    canPresent: false,
    maxLayers: 1
  };
  this.stageParameters = null;

  // "Private" members.
  this.waitingForPresent_ = false;
  this.layer_ = null;

  this.fullscreenElement_ = null;
  this.fullscreenWrapper_ = null;
  this.fullscreenElementCachedStyle_ = null;

  this.fullscreenEventTarget_ = null;
  this.fullscreenChangeHandler_ = null;
  this.fullscreenErrorHandler_ = null;

  this.wakelock_ = new WakeLock();
}
The base class for all VR displays.