Support SKMetalView on tvOS (#3114)

Author: MartinZikmund

binding/SkiaSharp/GRBackendRenderTarget.cs

@@ -30,7 +30,7 @@ public GRBackendRenderTarget (int width, int height, GRVkImageInfo vkImageInfo)
 			CreateVulkan (width, height, vkImageInfo);
 		}
 
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 
 		[Obsolete ("Use GRBackendRenderTarget(int width, int height, GRMtlTextureInfo mtlInfo) instead.")]
 		public GRBackendRenderTarget (int width, int height, int sampleCount, GRMtlTextureInfo mtlInfo)

binding/SkiaSharp/GRDefinitions.cs

@@ -87,13 +87,13 @@ public IntPtr TextureHandle {
 			readonly get => _textureHandle;
 			set {
 				_textureHandle = value;
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 				_texture = null;
 #endif
 			}
 		}
 
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 		private Metal.IMTLTexture _texture;
 		public GRMtlTextureInfo (Metal.IMTLTexture texture)
 		{

binding/SkiaSharp/GRMtlBackendContext.cs

@@ -1,7 +1,7 @@
 #nullable disable
 
 using System;
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 using Metal;
 #endif
 
@@ -25,13 +25,13 @@ public IntPtr QueueHandle {
 			get => _queueHandle;
 			set {
 				_queueHandle = value;
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 				_queue = null;
 #endif
 			}
 		}
 
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 		private IMTLDevice _device;
 		private IMTLCommandQueue _queue;
 

source/SkiaSharp.Views/SkiaSharp.Views/Platform/Apple/SKMetalView.cs

@@ -1,4 +1,4 @@
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 using System;
 using System.ComponentModel;
 using System.Diagnostics;
@@ -11,6 +11,8 @@
 namespace SkiaSharp.Views.iOS
 #elif __MACOS__
 namespace SkiaSharp.Views.Mac
+#elif __TVOS__
+namespace SkiaSharp.Views.tvOS
 #endif
 {
 	[Register(nameof(SKMetalView))]
@@ -104,7 +106,7 @@ void IMTKViewDelegate.DrawableSizeWillChange(MTKView view, CGSize size)
 			CanvasSize = size.ToSKSize();
 
 			if (Paused && EnableSetNeedsDisplay)
-#if __IOS__
+#if __IOS__ || __TVOS__
 				SetNeedsDisplay();
 #elif __MACOS__
 				NeedsDisplay = true;

source/SkiaSharp.Views/SkiaSharp.Views/Platform/Apple/SKPaintMetalSurfaceEventArgs.cs

@@ -1,10 +1,12 @@
-#if __IOS__ || __MACOS__
+#if __IOS__ || __MACOS__ || __TVOS__
 using System;
 
 #if __IOS__
 namespace SkiaSharp.Views.iOS
 #elif __MACOS__
 namespace SkiaSharp.Views.Mac
+#elif __TVOS__
+namespace SkiaSharp.Views.tvOS
 #endif
 {
 	public class SKPaintMetalSurfaceEventArgs : EventArgs