Make Paragraph._charWidths float[]

Runtime/ui/txt/layout.cs

             this._bounds.Set(_x, _y, _maxX - _x, _maxY - _y);
         }
 
-        public static void computeCharWidths(string text, int start, int count, TextStyle style, List<float> advances, int advanceOffset) {
+        public static void computeCharWidths(string text, int start, int count, TextStyle style, float[] advances, int advanceOffset) {
             char startingChar = text[start];
             if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
                 float advance = style.fontSize + style.letterSpacing;

Runtime/ui/txt/linebreaker.cs

         static List<int> _newLinePositions;
 
         TextBuff _textBuf;
-        List<float> _charWidths = new List<float>();
+        float[] _charWidths;
         List<int> _breaks = new List<int>();
         List<float> _widths = new List<float>();
         WordBreaker _wordBreaker = new WordBreaker();
         }
 
         public void resize(int size) {
-            if (this._charWidths.Count < size) {
-                NoAllocHelpersBridge<float>.ResizeList(this._charWidths, size);
+            if (this._charWidths == null || this._charWidths.Length < size) {
+                this._charWidths = new float[size];
             }
         }