Exposing Point & Rect types

tools/dom/src/Rectangle.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of html;
 
 /**
  * A class for representing two-dimensional rectangles.
  */
 class Rect {
   final num left;
   final num top;
   final num width;
   final num height;
 
-  Rect(this.left, this.top, this.width, this.height) {
-    if (width < 0) {
-      throw new ArgumentError(width);
-    }
-    if (height < 0) {
-      throw new ArgumentError(height);
-    }
-  }
+  const Rect(this.left, this.top, this.width, this.height);
 
   factory Rect.fromPoints(Point a, Point b) {
     var left;
     var width;
     if (a.x < b.x) {
       left = a.x;
       width = b.x - left;
     } else {
       left = b.x;
       width = a.x - left;
@@ skipping 99 matching lines @@
    * Truncates coordinates to integers and returns the result as a new
    * rectangle.
    */
   Rect toInt() => new Rect(left.toInt(), top.toInt(), width.toInt(),
       height.toInt());
 
   Point get topLeft => new Point(this.left, this.top);
   Point get bottomRight => new Point(this.left + this.width,
       this.top + this.height);
 }