Clean up some trait info loading code

Remove some methods that traits define to load their YAML values on their own.

OpenRA.Mods.Common/Traits/GainsExperience.cs

@@ -10,7 +10,6 @@
 
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Mods.Common.Effects;
 using OpenRA.Primitives;
 using OpenRA.Traits;
@@ -20,7 +19,7 @@ namespace OpenRA.Mods.Common.Traits
 	[Desc("This actor's experience increases when it has killed a GivesExperience actor.")]
 	public class GainsExperienceInfo : ITraitInfo, Requires<ValuedInfo>, Requires<UpgradeManagerInfo>
 	{
-		[FieldLoader.LoadUsing("LoadUpgrades", true)]
+		[FieldLoader.Require]
 		[Desc("Upgrades to grant at each level.",
 			"Key is the XP requirements for each level as a percentage of our own value.",
 			"Value is a list of the upgrade types to grant")]
@@ -33,15 +32,6 @@ namespace OpenRA.Mods.Common.Traits
 		public readonly bool SuppressLevelupAnimation = true;
 
 		public object Create(ActorInitializer init) { return new GainsExperience(init, this); }
-
-		static object LoadUpgrades(MiniYaml y)
-		{
-			MiniYaml upgrades = y.ToDictionary()["Upgrades"];
-
-			return upgrades.Nodes.ToDictionary(
-				kv => FieldLoader.GetValue<int>("(key)", kv.Key),
-				kv => FieldLoader.GetValue<string[]>("(value)", kv.Value.Value));
-		}
 	}
 
 	public class GainsExperience : ISync, IResolveOrder

OpenRA.Mods.Common/Traits/Infantry/TakeCover.cs

@@ -28,7 +28,6 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("Damage types that trigger prone state. Defined on the warheads.")]
 		public readonly string[] DamageTriggers = null;
 
-		[FieldLoader.LoadUsing("LoadModifiers")]
 		[Desc("Damage modifiers for each damage type (defined on the warheads) while the unit is prone.")]
 		public readonly Dictionary<string, int> DamageModifiers = new Dictionary<string, int>();
 
@@ -37,15 +36,6 @@ namespace OpenRA.Mods.Common.Traits
 		[SequenceReference(null, true)] public readonly string ProneSequencePrefix = "prone-";
 
 		public override object Create(ActorInitializer init) { return new TakeCover(init, this); }
-
-		public static object LoadModifiers(MiniYaml yaml)
-		{
-			var md = yaml.ToDictionary();
-
-			return md.ContainsKey("DamageModifiers")
-				? md["DamageModifiers"].ToDictionary(my => FieldLoader.GetValue<int>("(value)", my.Value))
-				: new Dictionary<string, int>();
-		}
 	}
 
 	public class TakeCover : Turreted, INotifyDamage, IDamageModifier, ISpeedModifier, ISync, IRenderInfantrySequenceModifier

OpenRA.Mods.Common/Traits/Infantry/TerrainModifiesDamage.cs

@@ -9,7 +9,6 @@
  #endregion
 
 using System.Collections.Generic;
-using System.Linq;
 using OpenRA.Mods.Common.Warheads;
 using OpenRA.Traits;
 
@@ -17,7 +16,7 @@ namespace OpenRA.Mods.Common.Traits
 {
 	public class TerrainModifiesDamageInfo : ITraitInfo
 	{
-		[FieldLoader.LoadUsing("LoadPercents", true)]
+		[FieldLoader.Require]
 		[Desc("Damage percentage for specific terrain types. 120 = 120%, 80 = 80%, etc.")]
 		public readonly Dictionary<string, int> TerrainModifier = null;
 
@@ -25,13 +24,6 @@ namespace OpenRA.Mods.Common.Traits
 		public readonly bool ModifyHealing = false;
 
 		public object Create(ActorInitializer init) { return new TerrainModifiesDamage(init.Self, this); }
-
-		static object LoadPercents(MiniYaml y)
-		{
-			return y.ToDictionary()["TerrainModifier"].Nodes.ToDictionary(
-				kv => FieldLoader.GetValue<string>("(key)", kv.Key),
-				kv => FieldLoader.GetValue<int>("(value)", kv.Value.Value));
-		}
 	}
 
 	public class TerrainModifiesDamage : IDamageModifier

OpenRA.Mods.Common/Traits/Render/RenderSprites.cs

@@ -29,7 +29,6 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("The sequence name that defines the actor sprites. Defaults to the actor name.")]
 		public readonly string Image = null;
 
-		[FieldLoader.LoadUsing("LoadFactionImages")]
 		[Desc("A dictionary of faction-specific image overrides.")]
 		public readonly Dictionary<string, string> FactionImages = null;
 
@@ -42,16 +41,6 @@ namespace OpenRA.Mods.Common.Traits
 		[Desc("Change the sprite image size.")]
 		public readonly float Scale = 1f;
 
-		protected static object LoadFactionImages(MiniYaml y)
-		{
-			MiniYaml images;
-
-			if (!y.ToDictionary().TryGetValue("FactionImages", out images))
-				return null;
-
-			return images.Nodes.ToDictionary(kv => kv.Key, kv => kv.Value.Value);
-		}
-
 		public virtual object Create(ActorInitializer init) { return new RenderSprites(init, this); }
 
 		public IEnumerable<IActorPreview> RenderPreview(ActorPreviewInitializer init)