Add a sky media service to make it possible to play a sound.

sky/sdk/example/widgets/piano.dart

Index: sky/sdk/example/widgets/piano.dart
diff --git a/sky/sdk/example/widgets/piano.dart b/sky/sdk/example/widgets/piano.dart
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+// 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 'package:mojom/media/media.mojom.dart';
+import 'package:mojom/mojo/url_response.mojom.dart';
+import 'package:sky/mojo/net/fetch.dart';
+import 'package:sky/mojo/shell.dart' as shell;
+import 'package:sky/rendering/box.dart';
+import 'package:sky/rendering/flex.dart';
+import 'package:sky/theme/colors.dart' as colors;
+import 'package:sky/widgets/basic.dart';
+
+// All of these sounds are marked as public domain at soundbible.
+const String chimes = "http://soundbible.com/grab.php?id=2030&type=wav";
+const String chainsaw = "http://soundbible.com/grab.php?id=1391&type=wav";
+const String stag = "http://soundbible.com/grab.php?id=2073&type=wav";
+const String frogs = "http://soundbible.com/grab.php?id=2033&type=wav";
+const String rattle = "http://soundbible.com/grab.php?id=2037&type=wav";
+const String iLoveYou = "http://soundbible.com/grab.php?id=2045&type=wav";
+
+class Key {
+  Key(this.color, this.soundUrl);
+
+  final Color color;
+  final String soundUrl;
+  MediaPlayerProxy player;
+
+  void down() {
+    if (player == null)
+      return;
+    player.ptr.seekTo(0);
+    player.ptr.start();
+  }
+
+  void up() {
+    if (player == null)
+      return;
+    player.ptr.pause();
+  }
+}
+
+class PianoApp extends App {
+  final List<Key> keys = [
+    new Key(colors.Red[500], chimes),
+    new Key(colors.Orange[500], chainsaw),
+    new Key(colors.Yellow[500], stag),
+    new Key(colors.Green[500], frogs),
+    new Key(colors.Blue[500], rattle),
+    new Key(colors.Purple[500], iLoveYou),
+  ];
+
+  PianoApp() {
+    loadSounds();
+  }
+
+  loadSounds() async {
+    MediaServiceProxy mediaService = new MediaServiceProxy.unbound();
+    shell.requestService(null, mediaService);
+
+    for (Key key in keys) {
+      MediaPlayerProxy player = new MediaPlayerProxy.unbound();
+      mediaService.ptr.createPlayer(player);
+
+      UrlResponse response = await fetchUrl(key.soundUrl);
+      await player.ptr.prepare(response.body);
+      key.player = player;
+    }
+    mediaService.close();
+    // Are we leaking all the player connections?
+    scheduleBuild();
+  }
+
+  Widget build() {
+    List<Widget> children = [];
+    for (Key key in keys) {
+      children.add(
+        new Listener(
+          child: new Flexible(
+            child: new Container(
+              decoration: new BoxDecoration(backgroundColor: key.color)
+            )
+          ),
+          onPointerCancel: (_) => key.up(),
+          onPointerDown: (_) => key.down(),
+          onPointerUp: (_) => key.up()
+        )
+      );
+    }
+
+    return new Flex(
+      children,
+      direction: FlexDirection.vertical
+    );
+  }
+}
+
+void main() {
+  runApp(new PianoApp());
+}