Merge pull request #114 from Unity-Technologies/zxw/fix_editor_panel_crash

fix an editor panel crash

com.unity.uiwidgets/Runtime/rendering/debug_overflow_indicator.cs

 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Runtime.CompilerServices;
-using Unity.UIWidgets.widgets;
 using UnityEngine;
 using Color = Unity.UIWidgets.ui.Color;
 using Gradient = Unity.UIWidgets.ui.Gradient;
         const float _indicatorFraction = 0.1f;
         const float _indicatorFontSizePixels = 7.5f;
         const float _indicatorLabelPaddingPixels = 1.0f;
-
-        static readonly TextStyle _indicatorTextStyle = new TextStyle(
-            color: new Color(0xFF900000),
-            fontSize: _indicatorFontSizePixels,
-            fontWeight: FontWeight.w800
-        );
-
-        static readonly Paint _indicatorPaint = new Paint();
-
-        static readonly Paint _labelBackgroundPaint = new Paint();
-
-        static readonly List<TextPainter> _indicatorLabel = new List<TextPainter>(4);
-
-        static DebugOverflowIndicatorMixin() {
-            _indicatorPaint.shader = Gradient.linear(
-                new Offset(0.0f, 0.0f),
-                new Offset(10.0f, 10.0f),
-                new List<Color> {_black, _yellow, _yellow, _black},
-                new List<float> {0.25f, 0.25f, 0.75f, 0.75f},
-                TileMode.repeated
-            );
-            _labelBackgroundPaint.color = new Color(0xFFFFFFFF);
-            _OverflowSide e = new _OverflowSide();
-            var len = Enum.GetNames(e.GetType()).Length;
-            for (int i = 0; i < len; i++) {
-                _indicatorLabel.Add(new TextPainter(textDirection: TextDirection.ltr));
-            }
-        }
 
         static readonly Dictionary<RenderObject, bool> _overflowReportNeeded = new Dictionary<RenderObject, Boolean>();
 
                 return;
             }
 
+            TextStyle _indicatorTextStyle = new TextStyle(
+                color: new Color(0xFF900000),
+                fontSize: _indicatorFontSizePixels,
+                fontWeight: FontWeight.w800
+            );
+            
+            Paint _indicatorPaint = new Paint{ shader = Gradient.linear(
+                new Offset(0.0f, 0.0f),
+                new Offset(10.0f, 10.0f),
+                new List<Color> {_black, _yellow, _yellow, _black},
+                new List<float> {0.25f, 0.25f, 0.75f, 0.75f},
+                TileMode.repeated
+            )};
+            
+            Paint _labelBackgroundPaint = new Paint{color = new Color(0xFFFFFFFF)};
+
-                
-                TextSpan textSpan = _indicatorLabel[(int) region.side].text as TextSpan;
-                if (textSpan?.text != region.label) {
-                    _indicatorLabel[(int) region.side].text = new TextSpan(
+                var textPainter = new TextPainter(textDirection: TextDirection.ltr) {
+                    text = new TextSpan(
-                        style: _indicatorTextStyle
-                    );
-                    _indicatorLabel[(int) region.side].layout();
-                }
+                        style: _indicatorTextStyle)
+                };
+                textPainter.layout();
-                Offset centerOffset = new Offset(-_indicatorLabel[(int) region.side].width / 2.0f, 0.0f);
-                Rect textBackgroundRect = centerOffset & _indicatorLabel[(int) region.side].size;
+                Offset centerOffset = new Offset(-textPainter.width / 2.0f, 0.0f);
+                Rect textBackgroundRect = centerOffset & textPainter.size;
-                _indicatorLabel[(int) region.side].paint(context.canvas, centerOffset);
+                textPainter.paint(context.canvas, centerOffset);
                 context.canvas.restore();
             }