Merge pull request #9412 from keveleigh/fix-reading-mode

Update legacy and XR SDK implementation for renderViewportScaleSlider

Author: David Kline

Assets/MRTK/Examples/Demos/ReadingMode/Scripts/ReadingModeSceneBehavior.cs

@@ -3,15 +3,9 @@
 
 using Microsoft.MixedReality.Toolkit.CameraSystem;
 using Microsoft.MixedReality.Toolkit.UI;
-using UnityEngine;
-
-#if UNITY_2019_3_OR_NEWER
 using Microsoft.MixedReality.Toolkit.Utilities;
-#endif // UNITY_2019_3_OR_NEWER
-
-#if !UNITY_2020_1_OR_NEWER
+using UnityEngine;
 using UnityEngine.XR;
-#endif // !UNITY_2020_1_OR_NEWER
 
 namespace Microsoft.MixedReality.Toolkit.Examples.Demos.ReadingMode
 {
@@ -35,20 +29,10 @@ private void Update()
 
             previousSliderValue = renderViewportScaleSlider.SliderValue;
 
-#if UNITY_2019_3_OR_NEWER
-            if (XRSubsystemHelpers.DisplaySubsystem != null)
-            {
-                XRSubsystemHelpers.DisplaySubsystem.scaleOfAllViewports = Mathf.Max(renderViewportScaleSlider.SliderValue, MinScale);
-                return;
-            }
-#endif // UNITY_2019_3_OR_NEWER
-
-#if !UNITY_2020_1_OR_NEWER
-            if (XRDevice.isPresent)
+            if (DeviceUtility.IsPresent)
             {
                 XRSettings.renderViewportScale = Mathf.Max(renderViewportScaleSlider.SliderValue, MinScale);
             }
-#endif // !UNITY_2020_1_OR_NEWER
         }
 
         public void EnableReadingMode()