ozone: demo: Add software support & use message loop

ui/ozone/demo/BUILD.gn

 # Copyright 2014 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.
 
 group("demo") {
   deps = [
-    ":ozone_egl_demo",
+    ":ozone_demo",
   ]
 }
 
-executable("ozone_egl_demo") {
+executable("ozone_demo") {
   sources = [
-    "egl_demo.cc",
+    "ozone_demo.cc",
   ]
 
   deps = [
     "//base",
     "//ui/gfx/geometry",
     "//ui/gl",
     "//ui/ozone",
   ]
 }