Make ~/, round, ceil, floor, truncate return ints. Remove toInt.

samples/swarm/swarm_ui_lib/touch/Scrollbar.dart

 // Copyright (c) 2011, 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 touch;
 
 /**
  * Implementation of a scrollbar for the custom scrolling behavior
  * defined in [:Scroller:].
  */
@@ skipping 191 matching lines @@
     }
     _refreshScrollRatio();
     int coordinate = _currentScrollVertical ? e.pageY : e.pageX;
     num delta = (coordinate - _currentScrollStartMouse) * _currentScrollRatio;
     if (delta != 0) {
       num x;
       num y;
       _currentScrollStartOffset -= delta;
       if (_currentScrollVertical) {
         x = _scroller.getHorizontalOffset();
-        y = _currentScrollStartOffset.toInt();
+        y = _currentScrollStartOffset.truncate();
       } else {
-        x = _currentScrollStartOffset.toInt();
+        x = _currentScrollStartOffset.truncate();
         y = _scroller.getVerticalOffset();
       }
       _scroller.setPosition(x, y);
     }
     _currentScrollStartMouse = coordinate;
   }
 
   void _onEnd(UIEvent e) {
     _scrollBarDragInProgress = false;
     // TODO(jacobr): make scrollbar less tightly coupled to the scroller.
@@ skipping 120 matching lines @@
     style.setProperty(cssPos, '${pos}px', '');
     if (_cachedSize[cssSize] != size) {
       _cachedSize[cssSize] = size;
       style.setProperty(cssSize, '${size}px', '');
     }
     if (element.parent == null) {
       _frame.nodes.add(element);
     }
   }
 }