Fixes for PR

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/Sampler2DShaderProperty.cs

 using System.Text;
 using UnityEngine;
 
-namespace UnityEditor.ShaderGraph
+/*namespace UnityEditor.ShaderGraph
 {
     [Serializable]
     public class Sampler2DShaderProperty : AbstractShaderProperty<object>
             return default(PreviewProperty);
         }
     }
-}
+}*/

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Scene/ObjectNode.cs

 namespace UnityEditor.ShaderGraph
 {
     [Title("Input", "Scene", "Object")]
-    public class ObjectNode : AbstractMaterialNode
+    public sealed class ObjectNode : AbstractMaterialNode
     {
         const string kOutputSlotName = "Position";
         const string kOutputSlot1Name = "Scale";
             UpdateNodeAfterDeserialization();
         }
 
-        public sealed override void UpdateNodeAfterDeserialization()
+        public override void UpdateNodeAfterDeserialization()
         {
             AddSlot(new Vector3MaterialSlot(OutputSlotId, kOutputSlotName, kOutputSlotName, SlotType.Output, Vector3.zero));
             AddSlot(new Vector3MaterialSlot(OutputSlot1Id, kOutputSlot1Name, kOutputSlot1Name, SlotType.Output, Vector3.zero));

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Scene/SceneDepthNode.cs

 using UnityEditor.ShaderGraph.Drawing.Controls;
 using System.Collections.Generic;
 
-namespace UnityEditor.ShaderGraph
+/*namespace UnityEditor.ShaderGraph
 {
     public enum SceneDepthMode
     {
 
     [Title("Input", "Scene", "Scene Depth")]
-    public class SceneDepthNode : AbstractMaterialNode, IGenerateProperties, IGeneratesBodyCode, IMayRequireScreenPosition
+    public sealed class SceneDepthNode : AbstractMaterialNode, IGenerateProperties, IGeneratesBodyCode, IMayRequireScreenPosition
     {
         const string kUVSlotName = "UV";
         const string kOutputSlotName = "Out";
             }
         }
 
-        public sealed override void UpdateNodeAfterDeserialization()
+        public override void UpdateNodeAfterDeserialization()
         {
             AddSlot(new ScreenPositionMaterialSlot(UVSlotId, kUVSlotName, kUVSlotName));
             AddSlot(new Vector1MaterialSlot(OutputSlotId, kOutputSlotName, kOutputSlotName, SlotType.Output, 0));
             return uvSlot.RequiresScreenPosition();
         }
     }
-}
+}*/

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Nodes/Input/Scene/ScreenNode.cs

 namespace UnityEditor.ShaderGraph
 {
     [Title("Input", "Scene", "Screen")]
-    public class ScreenNode : AbstractMaterialNode
+    public sealed class ScreenNode : AbstractMaterialNode
     {
         const string kOutputSlotName = "Width";
         const string kOutputSlot1Name = "Height";
             UpdateNodeAfterDeserialization();
         }
 
-        public sealed override void UpdateNodeAfterDeserialization()
+        public override void UpdateNodeAfterDeserialization()
         {
             AddSlot(new Vector1MaterialSlot(OutputSlotId, kOutputSlotName, kOutputSlotName, SlotType.Output, 0));
             AddSlot(new Vector1MaterialSlot(OutputSlot1Id, kOutputSlot1Name, kOutputSlot1Name, SlotType.Output, 0));