Rationalize Dart mojo and sky package structure

sky/framework/components/action_bar.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 '../layout.dart';
-import '../theme/view_configuration.dart';
-import 'material.dart';
-
-class ActionBar extends Component {
-  static final Style _style = new Style('''
-    align-items: center;
-    height: 56px;
-    padding: 0 8px;
-    transition: background-color 0.3s;
-    padding-top: ${kStatusBarHeight}px;''');
-
-  static Style _centerStyle = new Style('''
-    padding-left: 24px;''');
-
-  static FlexBoxParentData _centerLayoutSettings = new FlexBoxParentData()..flex = 1;
-
-  UINode left;
-  UINode center;
-  List<UINode> right;
-
-  ActionBar({
-    String key,
-    this.left,
-    this.center,
-    this.right
-  }) : super(key: key);
-
-  UINode build() {
-    List<UINode> children = [left, new StyleNode(new ParentDataNode(center, _centerLayoutSettings), _centerStyle)];
-
-    if (right != null)
-      children.addAll(right);
-
-    return new Material(
-      content: new FlexContainer(
-        style: _style,
-        children: children,
-        direction: FlexDirection.Row),
-      level: 2);
-  }
-}