Skip RequestCharactersInTexture in doLayout.

Runtime/ui/txt/layout.cs

                     advances, positions, advanceOffset, advance);
             }
             else {
-                font.RequestCharactersInTextureSafe(buff.text, style.UnityFontSize, style.UnityFontStyle);
+                // According to the logic of Paragraph.layout, it is assured that all the characters are requested
+                // in the texture before (in computing line breaks), so skip it here for optimization
+                // The only exception is the ellipsis, which is dealt with somewhere else.
+                // font.RequestCharactersInTextureSafe(buff.text, style.UnityFontSize, style.UnityFontStyle);
 
                 int wordstart = start == buff.size
                     ? start
             }
 
             return x;
+        }
+
+        public static void requireEllipsisInTexture(string text, TextStyle style) {
+            Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
+            font.RequestCharactersInTextureSafe(text, style.UnityFontSize, style.UnityFontStyle);
         }
 
         public void setTabStops(TabStops tabStops) {

Runtime/ui/txt/paragraph.cs

                     if (!string.IsNullOrEmpty(ellipsis) && !this._width.isInfinite() && !lineRange.hardBreak
                         && i == lineRuns.Count - 1 &&
                         (lineNumber == lineLimit - 1 || this._paragraphStyle.maxLines == null)) {
+                        
+                        // By now, all characters have been "RequestCharactersInTexture"d by computeLineBreaks
+                        // except the ellipsis, so Layout.doLayout skips calling RequestCharactersInTexture for
+                        // performance, and the ellipsis is handled here
+                        Layout.requireEllipsisInTexture(ellipsis, run.style);
+                        
                         float ellipsisWidth = Layout.measureText(runXOffset, ellipsisTextBuff, 0,
                             ellipsis.Length, run.style, null, 0, this._tabStops);
                         textAdvances.reset(textCount);