AudioManager: only use main looper for AudioPort event handler

Bug: 17336373.
Change-Id: I0a9a7012778f99acbf027ec2928ca222954ad0bd
diff --git a/media/java/android/media/AudioPortEventHandler.java b/media/java/android/media/AudioPortEventHandler.java
index 8d2c172..9db4994 100644
--- a/media/java/android/media/AudioPortEventHandler.java
+++ b/media/java/android/media/AudioPortEventHandler.java
@@ -47,10 +47,7 @@
         mListeners = new ArrayList<AudioManager.OnAudioPortUpdateListener>();
 
         // find the looper for our new event handler
-        Looper looper = Looper.myLooper();
-        if (looper == null) {
-            looper = Looper.getMainLooper();
-        }
+        Looper looper = Looper.getMainLooper();
 
         if (looper != null) {
             mHandler = new Handler(looper) {