Move "update asset" button to blackboard

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Inspector/GraphInspectorView.cs

-using System;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using UnityEditor.Experimental.UIElements;
 
         PersistentMesh m_PersistentMasterNodePreviewMesh;
 
+        public Action onUpdateAssetClick { get; set; }
+
         public GraphInspectorView(string assetName, PreviewManager previewManager, AbstractMaterialGraph graph)
         {
             persistenceKey = "GraphInspector";
                 var headerContainer = new VisualElement {name = "header"};
                 {
                     headerContainer.Add(new Label(assetName) {name = "title"});
+                    headerContainer.Add(new Button(() =>
+                    {
+                        if (onUpdateAssetClick != null) onUpdateAssetClick();
+                    }) { name = "save", text = "Save" });
                 }
                 topContainer.Add(headerContainer);
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/GraphEditorView.cs

         PreviewManager m_PreviewManager;
         SearchWindowProvider m_SearchWindowProvider;
 
-        public Action onUpdateAssetClick { get; set; }
+        public Action onUpdateAssetClick
+        {
+            get { return m_GraphInspectorView.onUpdateAssetClick; }
+            set { m_GraphInspectorView.onUpdateAssetClick = value; }
+        }
 
         public Action onConvertToSubgraphClick
         {
 
             m_ToolbarView = new ToolbarView { name = "TitleBar" };
             {
-                m_ToolbarView.Add(new ToolbarSpaceView());
-                m_ToolbarView.Add(new ToolbarSeparatorView());
-
-                var updateAssetButton = new ToolbarButtonView { text = "Update asset" };
-                updateAssetButton.AddManipulator(new Clickable(() =>
-                    {
-                        if (onUpdateAssetClick != null) onUpdateAssetClick();
-                    }));
-                m_ToolbarView.Add(updateAssetButton);
-
-                m_ToolbarView.Add(new ToolbarSeparatorView());
                 m_ToolbarView.Add(new ToolbarSpaceView());
                 m_ToolbarView.Add(new ToolbarSeparatorView());
 

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Resources/Styles/MaterialGraph.uss

     background-color: rgb(64, 64, 64);
     border-color: rgb(79, 79, 79);
     border-bottom-width: 1;
+    flex-direction: row;
+    justify-content: space-between;
 }
 
 GraphInspectorView > #top > #header > #title {