Caching initialization attempt, bool.Parse in WASM

src/Uno.UWP/Phone/Devices/Notification/VibrationDevice.Android.cs

@@ -12,17 +12,17 @@ namespace Windows.Phone.Devices.Notification
 	public partial class VibrationDevice
 	{
 		private const string Permission = "android.permission.VIBRATE";
-		
-		private readonly Vibrator _vibrator;
-
 		private static VibrationDevice _instance;
+		private static bool _initializationAttempted;
+
+		private readonly Vibrator _vibrator;
 
 		private VibrationDevice(Vibrator vibrator) =>
 			_vibrator = vibrator;
 
 		public static VibrationDevice GetDefault()
 		{
-			if (_instance == null)
+			if (!_initializationAttempted && _instance == null)
 			{
 				if (ContextCompat.CheckSelfPermission(Application.Context, Permission) == Android.Content.PM.Permission.Denied)
 				{
@@ -32,7 +32,8 @@ namespace Windows.Phone.Devices.Notification
 				if (vibrator != null && vibrator.HasVibrator)
 				{
 					_instance = new VibrationDevice(vibrator);
-				}				
+				}
+				_initializationAttempted = true;
 			}
 			return _instance;
 		}

src/Uno.UWP/Phone/Devices/Notification/VibrationDevice.wasm.cs

@@ -9,6 +9,7 @@ namespace Windows.Phone.Devices.Notification
 	{
 		private const string JsType = "Windows.Phone.Devices.Notification.VibrationDevice";
 		private static VibrationDevice _instance = null;
+		private static bool _initializationAttempted = false;
 
 		private VibrationDevice()
 		{
@@ -16,14 +17,15 @@ namespace Windows.Phone.Devices.Notification
 
 		public static VibrationDevice GetDefault()
 		{
-			if (_instance == null)
+			if (!_initializationAttempted && _instance == null)
 			{
 				var command = $"{JsType}.initialize()";
 				var initialized = Uno.Foundation.WebAssemblyRuntime.InvokeJS(command);
-				if (initialized.Equals("true", StringComparison.InvariantCultureIgnoreCase))
+				if (bool.Parse(initialized) == true)
 				{
-					 _instance = new VibrationDevice();
+					_instance = new VibrationDevice();
 				}
+				_initializationAttempted = true;
 			}
 			return _instance;
 		}