Parallax refactors (#7654)

Content.IntegrationTests/DummyParallaxManager.cs

@@ -1,25 +1,20 @@
 using System;
 using Content.Client.Parallax.Managers;
+using Content.Client.Parallax;
 using Robust.Client.Graphics;
+using Robust.Shared.Maths;
 
 namespace Content.IntegrationTests
 {
     public sealed class DummyParallaxManager : IParallaxManager
     {
-        public event Action<Texture> OnTextureLoaded
-        {
-            add
-            {
-            }
-            remove
-            {
-            }
-        }
-
-        public Texture ParallaxTexture => null;
+        public string ParallaxName { get; set; } = "";
+        public Vector2 ParallaxAnchor { get; set; }
+        public ParallaxLayerPrepared[] ParallaxLayers { get; } = {};
 
         public void LoadParallax()
         {
+            ParallaxName = "default";
         }
     }
 }