How to use the webvr-polyfill/src/util.isLandscapeMode function in webvr-polyfill

// Set the filter to world transform, depending on OS.
		if (this.isIOS) {
			this.filterToWorldQ.setFromAxisAngle(new MathUtil.Vector3(1, 0, 0), Math.PI / 2);
		} else {
			this.filterToWorldQ.setFromAxisAngle(new MathUtil.Vector3(1, 0, 0), -Math.PI / 2);
		}

		this.inverseWorldToScreenQ = new MathUtil.Quaternion();
		this.worldToScreenQ = new MathUtil.Quaternion();
		this.originalPoseAdjustQ = new MathUtil.Quaternion();
		this.originalPoseAdjustQ.setFromAxisAngle(new MathUtil.Vector3(0, 0, 1),
			-window.orientation * Math.PI / 180);

		this._setScreenTransform();
		// Adjust this filter for being in landscape mode.
		if (Util.isLandscapeMode()) {
			this.filterToWorldQ.multiply(this.inverseWorldToScreenQ);
		}

		// Keep track of a reset transform for resetSensor.
		this.resetQ = new MathUtil.Quaternion();

		this.deviceMotion.on("devicemotion", this._onDeviceMotionChange);
		this.enable();
	}
	enable() {