Report emoji texture image load issue.

Runtime/ui/painting/canvas_impl.cs

 using System;
 using System.Collections.Generic;
+using System.Net;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.material;
 using UnityEngine;
                 }
                 else {
                     Paint paintWithWhite = new Paint(p) {color = Colors.white};
+                    if (EmojiUtils.image == null) return;
                     layer.draws.Add(CanvasShader.tex(layer, paintWithWhite, mesh.resolveMesh(), EmojiUtils.image));
                 }
             };

Runtime/ui/txt/emoji.cs

 using System;
 using System.Collections.Generic;
+using Unity.UIWidgets.foundation;
 using UnityEngine;
 
 namespace Unity.UIWidgets.ui {
                             Resources.Load<Texture2D>("Emoji")
                         );
                     }
-                    catch (Exception) {
+                    catch (Exception e) {
+                        Debug.LogError(e.StackTrace);
                     }
                 }