Merge pull request #10208 from RoosterDragon/perf-comments

Added some performance comments

OpenRA.Game/Graphics/SpriteFont.cs

@@ -40,6 +40,7 @@ namespace OpenRA.Graphics
 
 			glyphs = new Cache<Pair<char, Color>, GlyphInfo>(CreateGlyph, Pair<char, Color>.EqualityComparer);
 
+			// PERF: Cache these delegates for Measure calls.
 			Func<char, float> characterWidth = character => glyphs[Pair.New(character, Color.White)].Advance;
 			lineWidth = line => line.Sum(characterWidth);
 

OpenRA.Game/Graphics/Viewport.cs

@@ -22,6 +22,7 @@ namespace OpenRA.Graphics
 	{
 		public static bool Includes(this ScrollDirection d, ScrollDirection s)
 		{
+			// PERF: Enum.HasFlag is slower and requires allocations.
 			return (d & s) == s;
 		}