Outside node control for UV slots

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

 using System;
 using UnityEditor.Graphing;
+using UnityEditor.ShaderGraph.Drawing.Slots;
+using UnityEngine.Experimental.UIElements;
 
 namespace UnityEditor.ShaderGraph
 {
             : base(slotId, displayName, shaderOutputName, SlotType.Input, Vector2.zero, shaderStage, hidden)
         {
             this.channel = channel;
+        }
+
+        public override VisualElement InstantiateControl()
+        {
+            return new UVSlotControlView(this);
         }
 
         public override string GetDefaultValue(GenerationMode generationMode)

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

     margin-right: 0;
 }
 
+UVSlotControlView > EnumField {
+    margin-top: 0;
+    margin-bottom: 0;
+    margin-left: 0;
+    margin-right: 0;
+    width: 40;
+}
+
 .edge.fromMatrix4, .edge.fromMatrix3, .edge.fromMatrix2 {
     edge-output-color: #8FC1DF;
 }

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/UVSlotControlView.cs

+using System;
+using UnityEditor.Experimental.UIElements;
+using UnityEditor.Graphing;
+using UnityEngine.Experimental.UIElements;
+
+namespace UnityEditor.ShaderGraph.Drawing.Slots
+{
+    public class UVSlotControlView : VisualElement
+    {
+        UVMaterialSlot m_Slot;
+
+        public UVSlotControlView(UVMaterialSlot slot)
+        {
+            m_Slot = slot;
+            var enumField = new EnumField(slot.channel);
+            enumField.OnValueChanged(OnValueChanged);
+            Add(enumField);
+        }
+
+        void OnValueChanged(ChangeEvent<Enum> evt)
+        {
+            var channel = (UVChannel) evt.newValue;
+            if (channel != m_Slot.channel)
+            {
+                m_Slot.owner.owner.owner.RegisterCompleteObjectUndo("Change UV Channel");
+                m_Slot.channel = channel;
+                if (m_Slot.owner.onModified != null)
+                    m_Slot.owner.onModified(m_Slot.owner, ModificationScope.Graph);
+            }
+        }
+    }
+}

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Views/Slots/UVSlotControlView.cs.meta

+fileFormatVersion: 2
+guid: f19b65893a414156825079dfc9a6dea3
+timeCreated: 1509961226