Add SerializableMesh

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

+using System;
+using UnityEngine;
+
+namespace UnityEditor.ShaderGraph
+{
+    [Serializable]
+    public class SerializableMesh
+    {
+        [SerializeField]
+        private string m_SerializedMesh;
+
+        [Serializable]
+        private class MeshHelper
+        {
+            public Mesh mesh;
+        }
+
+        public Mesh mesh
+        {
+            get
+            {
+                if (string.IsNullOrEmpty(m_SerializedMesh))
+                    return null;
+
+                var meshHelper = new MeshHelper();
+                EditorJsonUtility.FromJsonOverwrite(m_SerializedMesh, meshHelper);
+                return meshHelper.mesh;
+            }
+            set
+            {
+                if (mesh == value)
+                    return;
+
+                var meshHelper = new MeshHelper();
+                meshHelper.mesh = value;
+                m_SerializedMesh = EditorJsonUtility.ToJson(meshHelper, true);
+            }
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Data/Graphs/SerializableMesh.cs.meta

+fileFormatVersion: 2
+guid: 944c4fc9d004e7845adb3f86843ab742
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: