compiler warnings removed

Author: jasonm-unity

source/Core/FrameRecorder/Core/Editor/EnumHelper.cs

@@ -25,7 +25,6 @@ public static int GetMaskedIndexFromEnumValue<TEnum>(int value, int mask)
         {
             if (!typeof(TEnum).IsEnum) throw new ArgumentException("Arg not an enum");
             var values = Enum.GetValues(typeof(TEnum));
-            var result = new List<string>();
             for( int i = 0, j = -1; i < values.Length; i++ )
             {
                 var v = (int)values.GetValue(i);

source/Core/FrameRecorder/Core/Editor/RecorderWindow.cs

@@ -1,7 +1,6 @@
 using System;
 using UnityEngine.FrameRecorder;
 using UnityEngine;
-using UnityEngine.FrameRecorder;
 
 namespace UnityEditor.FrameRecorder
 {

source/Core/FrameRecorder/Recorders/PNG/Editor/PNGRecorderEditor.cs

@@ -20,7 +20,7 @@ static void ShowRecorderWindow()
             RecorderWindow.ShowAndPreselectCategory("Video");
         }
 
-        protected void OnEnable()
+        protected override void OnEnable()
         {
             base.OnEnable();