AIDLize IAudioFlinger

This change removes all the manual parceling code used in the
IAudioFlinger interface. In order to reduce impact on existing client
and server code to a minimum, the IAudioFlinger interface is preserved
and a new translation layer between IAudioFlinger and its AIDL
counterpart, IAudioFlingerService, is introduced:
- AudioFlingerClientAdapter is for use on the client side. It wraps an
  IAudioFlingerService instance and presents an IAudioFlinger
  interface.
- AudioFlingerServerAdapter is for use on the server side. It wraps an
  IAudioFlinger instance and presents an IAudioFlingerService.

Argument conversion an error checking is performed rigorously in the
translation layer.

Test: Audio-related CTS tests from CtsMediaTestCases
Bug: 160253486
Change-Id: Ibe35317e449b0faa3ef5336bb30f669106978a31
diff --git a/media/libaudioclient/AudioSystem.cpp b/media/libaudioclient/AudioSystem.cpp
index d163feb..72c65c1 100644
--- a/media/libaudioclient/AudioSystem.cpp
+++ b/media/libaudioclient/AudioSystem.cpp
@@ -71,7 +71,7 @@
             sp<IServiceManager> sm = defaultServiceManager();
             sp<IBinder> binder;
             do {
-                binder = sm->getService(String16("media.audio_flinger"));
+                binder = sm->getService(String16(IAudioFlinger::DEFAULT_SERVICE_NAME));
                 if (binder != 0)
                     break;
                 ALOGW("AudioFlinger not published, waiting...");
@@ -83,7 +83,8 @@
                 reportNoError = true;
             }
             binder->linkToDeath(gAudioFlingerClient);
-            gAudioFlinger = interface_cast<IAudioFlinger>(binder);
+            gAudioFlinger = new AudioFlingerClientAdapter(
+                    interface_cast<media::IAudioFlingerService>(binder));
             LOG_ALWAYS_FATAL_IF(gAudioFlinger == 0);
             afc = gAudioFlingerClient;
             // Make sure callbacks can be received by gAudioFlingerClient