Remove media service example (#6264)

This example is misleading because it relies on the old services model.
Let's remove it until #6263 is fixed.

examples/layers/services/media_service.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:async';
-
-import 'package:flutter_services/media.dart' as mojom;
-import 'package:flutter/material.dart';
-import 'package:flutter/rendering.dart';
-import 'package:flutter/services.dart';
-import 'package:flutter/http.dart' as http;
-import 'package:mojo/core.dart' as core;
-
-// 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 PianoKey {
-  PianoKey(this.color, this.soundUrl);
-
-  final Color color;
-  final String soundUrl;
-
-  final mojom.MediaPlayerProxy player = new mojom.MediaPlayerProxy.unbound();
-
-  bool get isPlayerOpen => player.ctrl.isOpen;
-
-  void down() {
-    if (!isPlayerOpen) return;
-    player.seekTo(0);
-    player.start();
-  }
-
-  void up() {
-    if (!isPlayerOpen) return;
-    player.pause();
-  }
-
-  Future<Null> load(mojom.MediaServiceProxy mediaService) async {
-    try {
-      mediaService.createPlayer(player);
-      http.Response response = await http.get(soundUrl);
-      core.MojoDataPipe pipe = new core.MojoDataPipe();
-      core.DataPipeFiller.fillHandle(pipe.producer, response.bodyBytes.buffer.asByteData());
-      player.prepare(pipe.consumer, (bool ignored) { });
-    } catch (e) {
-      print("Error: failed to load sound file $soundUrl");
-      player.close();
-    }
-  }
-}
-
-class PianoApp extends StatelessWidget {
-  final List<PianoKey> keys = <PianoKey>[
-    new PianoKey(Colors.red[500], chimes),
-    new PianoKey(Colors.orange[500], chainsaw),
-    new PianoKey(Colors.yellow[500], stag),
-    new PianoKey(Colors.green[500], frogs),
-    new PianoKey(Colors.blue[500], rattle),
-    new PianoKey(Colors.purple[500], iLoveYou),
-  ];
-
-  Future<Null> loadSounds() async {
-    mojom.MediaServiceProxy mediaService = shell.connectToApplicationService(
-      'mojo:media_service', mojom.MediaService.connectToService
-    );
-    try {
-      List<Future<Null>> pending = <Future<Null>>[];
-      for (PianoKey key in keys)
-        pending.add(key.load(mediaService));
-      await Future.wait(pending);
-    } finally {
-      mediaService.close();
-    }
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    List<Widget> children = <Widget>[];
-    for (PianoKey key in keys) {
-      children.add(new Flexible(
-        child: new Listener(
-          child: new Container(
-            decoration: new BoxDecoration(backgroundColor: key.color)
-          ),
-          onPointerCancel: (_) => key.up(),
-          onPointerDown: (_) => key.down(),
-          onPointerUp: (_) => key.up()
-        )
-      ));
-    }
-    return new Column(children: children);
-  }
-}
-
-Widget statusBox(Widget child) {
-  const Color mediumGray = const Color(0xff555555);
-  const Color darkGray = const Color(0xff222222);
-  return new Center(
-    child: new Container(
-      decoration: const BoxDecoration(
-        boxShadow: const <BoxShadow>[
-          const BoxShadow(
-            color: mediumGray, offset: const Offset(6.0, 6.0), blurRadius: 5.0)
-        ],
-        backgroundColor: darkGray
-      ),
-      height: 90.0,
-      padding: const EdgeInsets.all(8.0),
-      margin: const EdgeInsets.symmetric(horizontal: 50.0),
-      child: new Center(child: child)
-    )
-  );
-}
-
-Widget splashScreen() {
-  return statusBox(
-    new Text(
-      'Loading sound files!',
-      style: new TextStyle(fontSize: 18.0)
-    )
-  );
-}
-
-Future<Null> main() async {
-  runApp(splashScreen());
-
-  PianoApp app = new PianoApp();
-  // use "await" to make sure the sound files are loaded before we show the ui.
-  await app.loadSounds();
-  runApp(app);
-  // runApp() returns immediately so you can't put application cleanup code
-  // here.  Android apps can be killed at any time, so there's also no way to
-  // catch a close event to do cleanup. Therefore, although we appear to be
-  // leaking the "player" handles, this is working as intended and the operating
-  // system will clean up when the activity is killed.
-}