Update Button to be made of Material

sky/framework/components/material.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 '../theme/shadows.dart';
+import 'dart:collection';
+import 'dart:math';
 import 'dart:sky' as sky;
-import 'dart:collection';
 import 'ink_splash.dart';
 
 class Material extends Component {
   static const _splashesKey = const Object();
 
   static final Style _splashesStyle = new Style('''
     transform: translateX(0);
     position: absolute;
     top: 0;
     left: 0;
     right: 0;
     bottom: 0'''
   );
 
+  static final List<Style> shadowStyle = [
+    null,
+    new Style('box-shadow: ${Shadow[1]}'),
+    new Style('box-shadow: ${Shadow[2]}'),
+    new Style('box-shadow: ${Shadow[3]}'),
+    new Style('box-shadow: ${Shadow[4]}'),
+    new Style('box-shadow: ${Shadow[5]}'),
+  ];
+
   LinkedHashSet<SplashAnimation> _splashes;
 
-  Style style;
+  List<Style> styles;
+  String inlineStyle;
   List<Node> children;
+  int level;
 
-  Material({ Object key, this.style, this.children }) : super(key: key) {
+  Material({
+      Object key,
+      this.styles,
+      this.inlineStyle,
+      this.children,
+      this.level: 0 }) : super(key: key) {
     events.listen('gesturescrollstart', _cancelSplashes);
     events.listen('wheel', _cancelSplashes);
     events.listen('pointerdown', _startSplash);
   }
 
   Node build() {
     List<Node> childrenIncludingSplashes = [];
 
     if (_splashes != null) {
       childrenIncludingSplashes.add(new Container(
-        style: _splashesStyle,
+        styles: [_splashesStyle],
         children: new List.from(_splashes.map(
             (s) => new InkSplash(s.onStyleChanged))),
         key: 'Splashes'
       ));
     }
 
     if (children != null)
       childrenIncludingSplashes.addAll(children);
 
-    return new Container(key: 'Material', style: style,
-        children: childrenIncludingSplashes);
+    List<Style> stylesIncludingShadow = styles;
+    if (level > 0) {
+      stylesIncludingShadow = new List.from(styles);
+      stylesIncludingShadow.add(shadowStyle[level]);
+    }
+
+    return new Container(key: 'Material', styles: stylesIncludingShadow,
+        inlineStyle: inlineStyle, children: childrenIncludingSplashes);
   }
 
   sky.ClientRect _getBoundingRect() => (getRoot() as sky.Element).getBoundingClientRect();
 
   void _startSplash(sky.PointerEvent event) {
     setState(() {
       if (_splashes == null) {
         _splashes = new LinkedHashSet<SplashAnimation>();
       }
 
@@ skipping 27 matching lines @@
     }
 
     setState(() {
       _splashes.remove(splash);
       if (_splashes.length == 0) {
         _splashes = null;
       }
     });
   }
 }