aaudio: fix leak of AAudioBinderClient

Made it a Singleton that gets reused.

Bug: 37992613
Test: write_sine_callback.cpp
Change-Id: I63c045bd71d3bc1fc84f5fd4d7a6159fa5184c1c
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/media/libaaudio/src/binding/AAudioBinderClient.h b/media/libaaudio/src/binding/AAudioBinderClient.h
index ca2da29..e223376 100644
--- a/media/libaaudio/src/binding/AAudioBinderClient.h
+++ b/media/libaaudio/src/binding/AAudioBinderClient.h
@@ -17,6 +17,8 @@
 #ifndef ANDROID_AAUDIO_AAUDIO_BINDER_CLIENT_H
 #define ANDROID_AAUDIO_AAUDIO_BINDER_CLIENT_H
 
+#include <utils/Singleton.h>
+
 #include <aaudio/AAudio.h>
 #include "AAudioServiceDefinitions.h"
 #include "AAudioServiceInterface.h"
@@ -30,7 +32,8 @@
 
 namespace aaudio {
 
-class AAudioBinderClient : public AAudioServiceInterface {
+class AAudioBinderClient : public AAudioServiceInterface
+        , public android::Singleton<AAudioBinderClient> {
 
 public: