Cleanup of SkyBinding, and resultant yak shaving.

sky/sdk/lib/rendering/box.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:math' as math;
 import 'dart:sky' as sky;
 
 import 'package:vector_math/vector_math.dart';
 
 import '../framework/debug/utils.dart';
@@ skipping 174 matching lines @@
     value = 37 * value + minWidth.hashCode;
     value = 37 * value + maxWidth.hashCode;
     value = 37 * value + minHeight.hashCode;
     value = 37 * value + maxHeight.hashCode;
     return value;
   }
   String toString() => "BoxConstraints($minWidth<=w<$maxWidth, $minHeight<=h<$maxHeight)";
 }
 
 class BoxHitTestEntry extends HitTestEntry {
-  const BoxHitTestEntry(RenderBox target, this.localPosition)
-    : super(target);
-
+  const BoxHitTestEntry(HitTestTarget target, this.localPosition) : super(target);
   final Point localPosition;
 }
 
 class BoxParentData extends ParentData {
   Point _position = Point.origin;
   Point get position => _position;
   void set position(Point value) {
     assert(RenderObject.debugDoingLayout);
     _position = value;
   }
@@ skipping 871 matching lines @@
 
   void defaultPaint(RenderObjectDisplayList canvas) {
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is ParentDataType);
       canvas.paintChild(child, child.parentData.position);
       child = child.parentData.nextSibling;
     }
   }
 }