Add a shadow to the FloatingActionButton.

sky/sdk/lib/framework/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 'dart:typed_data';
 import 'object.dart';
+import '../painting/shadows.dart';
 import 'package:vector_math/vector_math.dart';
 import 'package:sky/framework/net/image_cache.dart' as image_cache;
 
 // GENERIC BOX RENDERING
 // Anything that has a concept of x, y, width, height is going to derive from this
 
 class EdgeDims {
   // used for e.g. padding
   const EdgeDims(this.top, this.right, this.bottom, this.left);
   const EdgeDims.all(double value)
@@ skipping 677 matching lines @@
 
   Paint _cachedBackgroundPaint;
   Paint get _backgroundPaint {
     if (_cachedBackgroundPaint == null) {
       Paint paint = new Paint();
 
       if (_decoration.backgroundColor != null)
         paint.color = _decoration.backgroundColor;
 
       if (_decoration.boxShadow != null) {
-        var builder = new sky.LayerDrawLooperBuilder();
-        for (BoxShadow boxShadow in _decoration.boxShadow) {
-          builder.addLayerOnTop(
-                new sky.DrawLooperLayerInfo()
-                  ..setPaintBits(-1)
-                  ..setOffset(boxShadow.offset.toPoint())
-                  ..setColorMode(sky.TransferMode.srcMode),
-                (Paint layerPaint) {
-              layerPaint.color = boxShadow.color;
-              layerPaint.setMaskFilter(
-                new sky.MaskFilter.Blur(sky.BlurStyle.normal,
-                                        boxShadow.blur,
-                                        highQuality: true));
-            });
-        }
-        builder.addLayerOnTop(new sky.DrawLooperLayerInfo(), (_) {});
+        var builder = new ShadowDrawLooperBuilder();
+        for (BoxShadow boxShadow in _decoration.boxShadow)
+          builder.addShadow(boxShadow.offset, boxShadow.color, boxShadow.blur);
         paint.setDrawLooper(builder.build());
       }
 
       _cachedBackgroundPaint = paint;
     }
 
     return _cachedBackgroundPaint;
   }
 
   void paint(RenderObjectDisplayList canvas) {
@@ skipping 286 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;
     }
   }
 }