Move the individual property definitions from client/base/Css to CSSStyleDeclaration.

client/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.
 
 /**
  * Implementation of a scrollbar for the custom scrolling behavior
  * defined in [:Scroller:].
  */
 class Scrollbar implements ScrollListener {
   /**
@@ skipping 280 matching lines @@
       show = true;
     }
     _toggleOpacity(_verticalElement, show);
     _toggleOpacity(_horizontalElement, show);
   }
 
   _toggleOpacity(Element element, bool show) {
     if (show) {
       element.style.removeProperty("opacity");
     } else {
-      Css.setOpacity(element.style, '0');
+      element.style.opacity = '0';
     }
   }
 
   num _defaultScrollSize(num frameSize, num contentSize) {
     return GoogleMath.clamp(
         (frameSize -_PADDING_LENGTH * 2) * frameSize / contentSize,
         _MIN_SIZE, frameSize -_PADDING_LENGTH * 2);
   }
 
   /**
@@ skipping 29 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);
     }
   }
 }