Add object field attribute control

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/SubGraph/MasterRemapNode.cs

 using System.Collections.Generic;
 using System.Linq;
 using UnityEditor;
+using UnityEditor.MaterialGraph.Drawing.Controls;
 using UnityEngine.Graphing;
 
 namespace UnityEngine.MaterialGraph
         }
 
 #if UNITY_EDITOR
+        [ObjectControl("Remap")]
         public MasterRemapGraphAsset remapGraphAsset
         {
             get

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/SubGraph/SubGraphNode.cs

 using System;
 using System.Linq;
+using UnityEditor.MaterialGraph.Drawing.Controls;
 #if UNITY_EDITOR
 using UnityEditor;
 #endif
         }
 
 #if UNITY_EDITOR
+        [ObjectControl("Subgraph")]
         public MaterialSubGraphAsset subGraphAsset
         {
             get

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Controls/ObjectControl.cs

+using System;
+using System.Reflection;
+using UnityEngine;
+using UnityEngine.Experimental.UIElements;
+using UnityEngine.MaterialGraph;
+using Object = UnityEngine.Object;
+
+namespace UnityEditor.MaterialGraph.Drawing.Controls
+{
+    [AttributeUsage(AttributeTargets.Property)]
+    public class ObjectControlAttribute : Attribute, IControlAttribute
+    {
+        string m_Label;
+
+        public ObjectControlAttribute(string label = null)
+        {
+            m_Label = label;
+        }
+
+        public VisualElement InstantiateControl(AbstractMaterialNode node, PropertyInfo propertyInfo)
+        {
+            return new ObjectControlView(m_Label, node, propertyInfo);
+        }
+    }
+
+    public class ObjectControlView : VisualElement
+    {
+        AbstractMaterialNode m_Node;
+        PropertyInfo m_PropertyInfo;
+        GUIContent m_Label;
+
+        public ObjectControlView(string label, AbstractMaterialNode node, PropertyInfo propertyInfo)
+        {
+            if (!typeof(Object).IsAssignableFrom(propertyInfo.PropertyType))
+                throw new ArgumentException("Property must be assignable to UnityEngine.Object.");
+            m_Node = node;
+            m_PropertyInfo = propertyInfo;
+            m_Label = new GUIContent(label ?? propertyInfo.Name);
+            Add(new IMGUIContainer(OnGUIHandler));
+        }
+
+        void OnGUIHandler()
+        {
+            var value = (Object) m_PropertyInfo.GetValue(m_Node, null);
+            using (var changeCheckScope = new EditorGUI.ChangeCheckScope())
+            {
+                value = EditorGUILayout.MiniThumbnailObjectField(m_Label, value, m_PropertyInfo.PropertyType);
+                if (changeCheckScope.changed)
+                    m_PropertyInfo.SetValue(m_Node, value, null);
+            }
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Controls/ObjectControl.cs.meta

+fileFormatVersion: 2
+guid: 3f483132ae7b4689b20fd6b8c59633b5
+timeCreated: 1507900115

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Presenters/Nodes/RemapMasterNodePresenter.cs.meta

-fileFormatVersion: 2
-guid: 4bd257f009292e44aa3616abf24d3327
-timeCreated: 1481188375
-licenseType: Pro
-MonoImporter:
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Presenters/Nodes/SubgraphNodePresenter.cs.meta

-fileFormatVersion: 2
-guid: eefa32eb807a2fc4c961b1f2277753e6
-timeCreated: 1478610369
-licenseType: Pro
-MonoImporter:
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Presenters/Nodes/SubgraphNodePresenter.cs

-using System;
-using System.Collections.Generic;
-using UnityEngine;
-using UnityEngine.MaterialGraph;
-
-namespace UnityEditor.MaterialGraph.Drawing
-{
-    [Serializable]
-    class SubgraphContolPresenter : GraphControlPresenter
-    {
-        public override void OnGUIHandler()
-        {
-            base.OnGUIHandler();
-
-            var subGraphNode = node as SubGraphNode;
-            if (subGraphNode == null)
-                return;
-
-            subGraphNode.subGraphAsset = (MaterialSubGraphAsset)EditorGUILayout.MiniThumbnailObjectField(
-                    new GUIContent("Subgraph"),
-                    subGraphNode.subGraphAsset,
-                    typeof(MaterialSubGraphAsset), null);
-        }
-
-        public override float GetHeight()
-        {
-            return EditorGUIUtility.singleLineHeight + 2 * EditorGUIUtility.standardVerticalSpacing;
-        }
-    }
-
-    [Serializable]
-    public class SubgraphNodePresenter : MaterialNodePresenter
-    {
-        protected override IEnumerable<GraphControlPresenter> GetControlData()
-        {
-            var instance = CreateInstance<SubgraphContolPresenter>();
-            instance.Initialize(node);
-            return new List<GraphControlPresenter> { instance };
-        }
-    }
-}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Presenters/Nodes/RemapMasterNodePresenter.cs

-using System;
-using System.Collections.Generic;
-using UnityEngine;
-using UnityEngine.MaterialGraph;
-
-namespace UnityEditor.MaterialGraph.Drawing
-{
-    [Serializable]
-    class RemapContolPresenter : GraphControlPresenter
-    {
-        public override void OnGUIHandler()
-        {
-            base.OnGUIHandler();
-
-            var remapNode = node as MasterRemapNode;
-            if (remapNode == null)
-                return;
-
-            remapNode.remapGraphAsset = (MasterRemapGraphAsset)EditorGUILayout.MiniThumbnailObjectField(
-                new GUIContent("Remap"),
-                remapNode.remapGraphAsset,
-                typeof(MasterRemapGraphAsset), null);
-        }
-
-        public override float GetHeight()
-        {
-            return EditorGUIUtility.singleLineHeight + 2 * EditorGUIUtility.standardVerticalSpacing;
-        }
-    }
-
-    [Serializable]
-    public class MasterRemapNodePresenter : MaterialNodePresenter
-    {
-        protected override IEnumerable<GraphControlPresenter> GetControlData()
-        {
-            var instance = CreateInstance<RemapContolPresenter>();
-            instance.Initialize(node);
-            return new List<GraphControlPresenter> { instance };
-        }
-    }
-}