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

sky/apk/demo/BUILD.gn

 # 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.
 
 assert(is_android)
 
 import("//build/config/android/config.gni")
 import("//build/config/android/rules.gni")
 import("//sky/apk/rules.gni")
 
 android_library("java") {
   java_files = [
     "org/domokit/sky/demo/SkyDemoActivity.java",
     "org/domokit/sky/demo/SkyDemoApplication.java",
   ]
 
   deps = [
     "//base:base_java",
     "//mojo/public/java:bindings",
     "//mojo/public/java:system",
     "//mojo/services/keyboard/public/interfaces:interfaces_java",
     "//mojo/services/sensors/public/interfaces:interfaces_java",
     "//services/keyboard",
     "//services/sensors:sensors_lib",
     "//sky/services/intents:intents_lib",
     "//sky/services/intents:interfaces_java",
+    "//sky/services/media:media_lib",
+    "//sky/services/media:interfaces_java",
     "//sky/shell:java",
   ]
 }
 
 sky_apk("demo") {
   apk_name = "SkyDemo"
   android_manifest = "AndroidManifest.xml"
   deps = [
     ":java",
     ":demo_resources",
   ]
 }
 
 android_resources("demo_resources") {
   resource_dirs = [ "res" ]
   android_manifest = "AndroidManifest.xml"
 }