add icon constraints to input_decorator

com.unity.uiwidgets/Runtime/material/input_decorator.cs

                     widthFactor: 1.0f,
                     heightFactor: 1.0f,
                     child: new ConstrainedBox(
-                        constraints: new BoxConstraints(minWidth: 48.0f, minHeight: 48.0f),
+                        constraints: this.decoration?.prefixIconConstraints ?? new BoxConstraints(minWidth: 48.0f, minHeight: 48.0f),
                         child: IconTheme.merge(
                             data: new IconThemeData(
                                 color: iconColor,
                     widthFactor: 1.0f,
                     heightFactor: 1.0f,
                     child: new ConstrainedBox(
-                        constraints: new BoxConstraints(minWidth: 48.0f, minHeight: 48.0f),
+                        constraints: this.decoration?.suffixIconConstraints ?? new BoxConstraints(minWidth: 48.0f, minHeight: 48.0f),
                         child: IconTheme.merge(
                             data: new IconThemeData(
                                 color: iconColor,
             bool? isDense = null,
             EdgeInsets contentPadding = null,
             Widget prefixIcon = null,
+            BoxConstraints prefixIconConstraints = null,
+            BoxConstraints suffixIconConstraints = null,
             Widget suffix = null,
             string suffixText = null,
             TextStyle suffixStyle = null,
             this.prefix = prefix;
             this.prefixText = prefixText;
             this.prefixIcon = prefixIcon;
+            this.prefixIconConstraints = prefixIconConstraints;
+            this.suffixIconConstraints = suffixIconConstraints;
             this.suffixStyle = suffixStyle;
             this.counter = counter;
             this.counterText = counterText;
                 isDense: false,
                 contentPadding: EdgeInsets.zero,
                 prefixIcon: null,
+                prefixIconConstraints: null,
+                suffixIconConstraints: null,
                 suffixText: null,
                 suffixStyle: null,
                 counter: null,
         public bool isCollapsed;
 
         public readonly Widget prefixIcon;
+
+        public readonly BoxConstraints prefixIconConstraints;
 
         public readonly Widget prefix;
 
 
         public readonly Widget suffixIcon;
 
+        public readonly BoxConstraints suffixIconConstraints;
+
         public readonly Widget suffix;
 
         public readonly string suffixText;
             bool? isDense = null,
             EdgeInsets contentPadding = null,
             Widget prefixIcon = null,
+            BoxConstraints prefixIconConstraints = null,
+            BoxConstraints suffixIconConstraints = null,
             Widget suffix = null,
             string suffixText = null,
             TextStyle suffixStyle = null,
                 isDense: isDense ?? this.isDense,
                 contentPadding: contentPadding ?? this.contentPadding,
                 prefixIcon: prefixIcon ?? this.prefixIcon,
+                prefixIconConstraints: prefixIconConstraints ?? this.prefixIconConstraints,
+                suffixIconConstraints: suffixIconConstraints ?? this.suffixIconConstraints,
                 suffix: suffix ?? this.suffix,
                 suffixText: suffixText ?? this.suffixText,
                 suffixStyle: suffixStyle ?? this.suffixStyle,
                    && Equals(other.contentPadding, this.contentPadding)
                    && Equals(other.isCollapsed, this.isCollapsed)
                    && Equals(other.prefixIcon, this.prefixIcon)
+                   && Equals(other.prefixIconConstraints, this.prefixIconConstraints)
+                   && Equals(other.suffixIconConstraints, this.suffixIconConstraints)
                    && Equals(other.suffix, this.suffix)
                    && Equals(other.suffixText, this.suffixText)
                    && Equals(other.suffixStyle, this.suffixStyle)
                 hashCode = (hashCode * 397) ^ this.border.GetHashCode();
                 hashCode = (hashCode * 397) ^ this.enabled.GetHashCode();
                 hashCode = (hashCode * 397) ^ this.prefixIcon.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.prefixIconConstraints.GetHashCode();
+                hashCode = (hashCode * 397) ^ this.suffixIconConstraints.GetHashCode();
                 hashCode = (hashCode * 397) ^ this.suffix.GetHashCode();
                 hashCode = (hashCode * 397) ^ this.suffixText.GetHashCode();
                 hashCode = (hashCode * 397) ^ this.suffixStyle.GetHashCode();
                 description.Add($"prefixIcon: ${this.prefixIcon}");
             }
 
+            if (this.prefixIconConstraints != null) {
+                description.Add($"prefixIconConstraints: ${this.prefixIconConstraints}");
+            }
+
             if (this.prefix != null) {
                 description.Add($"prefix: ${this.prefix}");
             }
 
             if (this.suffixIcon != null) {
                 description.Add($"suffixIcon: ${this.suffixIcon}");
+            }
+            
+            if (this.suffixIconConstraints != null) {
+                description.Add($"suffixIconConstraints: ${this.suffixIconConstraints}");
             }
 
             if (this.suffix != null) {