Converting Element.client*, offset* and Screen.avail* over to Rects

samples/swarm/swarm_ui_lib/layout/ViewLayout.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 layout;
 
 /** The interface that the layout algorithms use to talk to the view. */
 abstract class Positionable {
   ViewLayout get layout;
 
@@ skipping 90 matching lines @@
     }
   }
 
   static bool hasCustomLayout(Positionable view) {
     return view.customStyle['display'] == "-dart-grid";
   }
 
   CssStyleDeclaration get _style => layoutParams.style;
 
   void cacheExistingBrowserLayout() {
-    _offsetWidth = view.node.offsetWidth;
-    _offsetHeight = view.node.offsetHeight;
+    _offsetWidth = view.node.offset.width;
+    _offsetHeight = view.node.offset.height;
   }
 
   int get currentWidth {
     return _offsetWidth;
   }
 
   int get currentHeight {
     return _offsetHeight;
   }
 
@@ skipping 104 matching lines @@
       // For an unset max-content size, use the actual size
       return size;
     }
     if (style.endsWith('%')) {
       num percent = double.parse(style.substring(0, style.length - 1));
       return ((percent / 100) * parentSize).toInt();
     }
     return _toPixels(style);
   }
 }