[dotnet] Annotate nullable reference types on input devices (#14804)

* [dotnet] Annotate nullable reference types on input devices

* remove unnecessary `_`

* Use block-body methods in `InputDevice`

* Revert `WheelInputDevice.ConvertElement` and `PointerInputDevice.ConvertElement`

* Make methods always body-blocked

* Add null check to `CreatePointerMove`

* Add null check to `CreateWheelScroll`

* Do not demand for `PointerMoveInteraction.target` to be not-null

dotnet/src/webdriver/Interactions/InputDevice.cs

@@ -21,36 +21,34 @@
 using System.Collections.Generic;
 using System.Globalization;
 
+#nullable enable
+
 namespace OpenQA.Selenium.Interactions
 {
     /// <summary>
     /// Base class for all input devices for actions.
     /// </summary>
     public abstract class InputDevice
     {
-        private string deviceName;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="InputDevice"/> class.
         /// </summary>
         /// <param name="deviceName">The unique name of the input device represented by this class.</param>
+        /// <exception cref="ArgumentException">If <paramref name="deviceName"/> is <see langword="null"/> or <see cref="string.Empty"/>.</exception>
         protected InputDevice(string deviceName)
         {
             if (string.IsNullOrEmpty(deviceName))
             {
                 throw new ArgumentException("Device name must not be null or empty", nameof(deviceName));
             }
 
-            this.deviceName = deviceName;
+            this.DeviceName = deviceName;
         }
 
         /// <summary>
         /// Gets the unique name of this input device.
         /// </summary>
-        public string DeviceName
-        {
-            get { return this.deviceName; }
-        }
+        public string DeviceName { get; }
 
         /// <summary>
         /// Gets the kind of device for this input device.
@@ -90,7 +88,7 @@ public Interaction CreatePause(TimeSpan duration)
         /// <returns>A hash code for the current <see cref="InputDevice"/>.</returns>
         public override int GetHashCode()
         {
-            return this.deviceName.GetHashCode();
+            return this.DeviceName.GetHashCode();
         }
 
         /// <summary>
@@ -99,7 +97,7 @@ public override int GetHashCode()
         /// <returns>A string that represents the current <see cref="InputDevice"/>.</returns>
         public override string ToString()
         {
-            return string.Format(CultureInfo.InvariantCulture, "{0} input device [name: {1}]", this.DeviceKind, this.deviceName);
+            return string.Format(CultureInfo.InvariantCulture, "{0} input device [name: {1}]", this.DeviceKind, this.DeviceName);
         }
     }
 }

dotnet/src/webdriver/Interactions/KeyInputDevice.cs

@@ -21,6 +21,8 @@
 using System.Collections.Generic;
 using System.Globalization;
 
+#nullable enable
+
 namespace OpenQA.Selenium.Interactions
 {
     /// <summary>
@@ -40,6 +42,7 @@ public KeyInputDevice()
         /// Initializes a new instance of the <see cref="KeyInputDevice"/> class, given the device's name.
         /// </summary>
         /// <param name="deviceName">The unique name of this input device.</param>
+        /// <exception cref="ArgumentException">If <paramref name="deviceName"/> is <see langword="null"/> or <see cref="string.Empty"/>.</exception>
         public KeyInputDevice(string deviceName)
             : base(deviceName)
         {
@@ -48,10 +51,7 @@ public KeyInputDevice(string deviceName)
         /// <summary>
         /// Gets the type of device for this input device.
         /// </summary>
-        public override InputDeviceKind DeviceKind
-        {
-            get { return InputDeviceKind.Key; }
-        }
+        public override InputDeviceKind DeviceKind => InputDeviceKind.Key;
 
         /// <summary>
         /// Converts this input device into an object suitable for serializing across the wire.
@@ -115,27 +115,23 @@ public override string ToString()
 
         private class TypingInteraction : Interaction
         {
-            private string type;
-            private string value;
+            private readonly string type;
 
             public TypingInteraction(InputDevice sourceDevice, string type, char codePoint)
                 : base(sourceDevice)
             {
                 this.type = type;
-                this.value = codePoint.ToString();
+                this.Value = codePoint.ToString();
             }
 
-            protected string Value
-            {
-                get { return this.value; }
-            }
+            protected string Value { get; }
 
             public override Dictionary<string, object> ToDictionary()
             {
                 Dictionary<string, object> toReturn = new Dictionary<string, object>();
 
                 toReturn["type"] = this.type;
-                toReturn["value"] = this.value;
+                toReturn["value"] = this.Value;
 
                 return toReturn;
             }