Revert initializing formals change in client code

client/touch/Scroller.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 custom scrolling behavior.
  * This behavior overrides native scrolling for an area. This area can be a
  * single defined part of a page, the entire page, or several different parts
  * of a page.
  *
@@ skipping 116 matching lines @@
 
   Size _scrollSize;
   Size _contentSize;
   Coordinate _minPoint;
   bool _isStopping = false;
   Coordinate _contentStartOffset;
   bool _started = false;
   bool _activeGesture = false;
   ScrollWatcher _scrollWatcher;
 
-  Scroller(Element scrollableElem, [verticalEnabled = false,
-           horizontalEnabled = false,
+  Scroller(Element scrollableElem, [this.verticalEnabled = false,
+           this.horizontalEnabled = false,
            momentumEnabled = true,
            lookupContentSizeDelegate = null,
            num defaultDecelerationFactor = 1,
            int scrollTechnique = null, bool capture = false])
-      : this.verticalEnabled = verticalEnabled,
-        this.horizontalEnabled = horizontalEnabled,
-        this._momentumEnabled = momentumEnabled,
-        this._lookupContentSizeDelegate = lookupContentSizeDelegate,
+      : _momentumEnabled = momentumEnabled,
+        _lookupContentSizeDelegate = lookupContentSizeDelegate,
         _element = scrollableElem,
         _frame = scrollableElem.parent,
         _scrollTechnique = scrollTechnique !== null
             ? scrollTechnique : ScrollerScrollTechnique.TRANSFORM_3D,
         _minPoint = new Coordinate(0, 0),
         _maxPoint = new Coordinate(0, 0),
         _maxOffset = new Coordinate(0, 0),
         _minOffset = new Coordinate(0, 0),
         _contentOffset = new Coordinate(0, 0) {
     _touchHandler = new TouchHandler(this, scrollableElem.parent);
@@ skipping 567 matching lines @@
     for (EventListener listener in _listeners) {
       listener(evt);
     }
   }
 }
 
 class ScrollerScrollTechnique {
   static final TRANSFORM_3D = 1;
   static final RELATIVE_POSITIONING = 2;
 }