Use `Brushes.*` instead of creating new ones from `Color` constants

src/BizHawk.Client.EmuHawk/CustomControls/ControlRenderer/GdiPlusRenderer.cs

@@ -8,8 +8,10 @@ namespace BizHawk.Client.EmuHawk.CustomControls
 
 		private readonly Pen _currentPen = Pens.Black.GetMutableCopy();
 
-		private readonly SolidBrush _currentBrush = new SolidBrush(Color.Black);
-		private readonly SolidBrush _currentStringBrush = new SolidBrush(Color.Black);
+		private readonly SolidBrush _currentBrush = ((SolidBrush) Brushes.Black).GetMutableCopy();
+
+		private readonly SolidBrush _currentStringBrush = ((SolidBrush) Brushes.Black).GetMutableCopy();
+
 		private Font _currentFont;
 		private bool _rotateString;
 

src/BizHawk.Client.EmuHawk/CustomControls/ViewportPanel.cs

@@ -73,8 +73,8 @@ namespace BizHawk.Client.EmuHawk
 				}
 				else
 				{
-					using (var sb = new SolidBrush(Color.Black))
 					{
+						var sb = Brushes.Black;
 						g.FillRectangle(sb, _bmp.Width, 0, Width - _bmp.Width, Height);
 						g.FillRectangle(sb, 0, _bmp.Height, _bmp.Width, Height - _bmp.Height);
 					}

src/BizHawk.Client.EmuHawk/Extensions/DrawingExtensions.cs

@@ -6,6 +6,10 @@ namespace BizHawk.Client.EmuHawk
 {
 	public static class DrawingExtensions
 	{
+		public static T GetMutableCopy<T>(this T b)
+			where T : Brush
+			=> (T) b.Clone();
+
 		public static Pen GetMutableCopy(this Pen p)
 			=> (Pen) p.Clone();
 	}

src/BizHawk.Client.EmuHawk/tools/NES/PaletteViewer.cs

@@ -5,8 +5,9 @@ namespace BizHawk.Client.EmuHawk
 {
 	public sealed class PaletteViewer : Control
 	{
-		private readonly SolidBrush BgPalettesBrush = new SolidBrush(Color.Black);
-		private readonly SolidBrush SpritePalettesBrush = new SolidBrush(Color.Black);
+		private readonly SolidBrush BgPalettesBrush = ((SolidBrush) Brushes.Black).GetMutableCopy();
+
+		private readonly SolidBrush SpritePalettesBrush = ((SolidBrush) Brushes.Black).GetMutableCopy();
 
 		public class Palette
 		{