Get rid of {Run,Terminate}MainApplication(), and more ApplicationDelegate conversion.

examples/audio_play_test/play_wav.cc

Index: examples/audio_play_test/play_wav.cc
diff --git a/examples/audio_play_test/play_wav.cc b/examples/audio_play_test/play_wav.cc
index a05fe2617683915cc9311909d9b9993c4124b10e..ee3dd3208738ce53ea29e63f03432806f3382cc1 100644
--- a/examples/audio_play_test/play_wav.cc
+++ b/examples/audio_play_test/play_wav.cc
@@ -557,5 +557,5 @@ void PlayWAVApp::Shutdown() {
 
 MojoResult MojoMain(MojoHandle app_request) {
   mojo::media::audio::examples::PlayWAVApp play_wav_app;
-  return mojo::RunMainApplication(app_request, &play_wav_app);
+  return mojo::RunApplication(app_request, &play_wav_app);
 }