[Effen] Port fn.dart from the legacy sky.Node backend to the RenderNode backend, which is currently…

sky/framework/components/ink_well.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 '../fn.dart';
 import 'dart:collection';
 import 'dart:sky' as sky;
 import 'ink_splash.dart';
 import 'scrollable.dart';
 
@@ skipping 27 matching lines @@
     return new EventListenerNode(
       new Container(
         style: _containmentStyleHack,
         inlineStyle: inlineStyle,
         children: childrenIncludingSplashes),
       onGestureTapDown: _startSplash,
       onGestureTap: _confirmSplash
     );
   }
 
-  sky.ClientRect _getBoundingRect() => (getRoot() as sky.Element).getBoundingClientRect();
-
   void _startSplash(sky.GestureEvent event) {
     setState(() {
       if (_splashes == null)
         _splashes = new LinkedHashSet<SplashController>();
       var splash;
-      splash = new SplashController(_getBoundingRect(), event.x, event.y,
+      var root = getRoot();
+      splash = new SplashController(root.rect, event.x, event.y,
                                     pointer: event.primaryPointer,
                                     onDone: () { _splashDone(splash); });
       _splashes.add(splash);
       UINode node = parent;
       while (node != null) {
         if (node is Scrollable)
           node.registerScrollClient(this);
         node = node.parent;
       }
     });
@@ skipping 42 matching lines @@
   void _splashDone(SplashController splash) {
     if (_splashes == null)
       return;
     setState(() {
       _splashes.remove(splash);
       if (_splashes.length == 0)
         _splashes = null;
     });
   }
 }