AudioService: Add the service's message queue to the dump

Clogged queue means UI and other commands can not reach
the service and will cause volume controls to malfunction.

Example dump snippet:

Message handler (watch for unhandled messages):
  Handler (com.android.server.audio.AudioService$AudioHandler) {a904698} @ 61825
    Looper (AudioService, tid 118) {6808ef1}
      Message 0: { when=-52s689ms what=25 ... }
      Message 1: { when=-52s8ms what=8 ... }
      Message 2: { when=-52s4ms what=8 ... }
      ...
      Message 35: { when=-2s436ms what=0 ... }
      (Total messages: 36, polling=false, quitting=false)

This indicates that the command queue is not being processed
because the handler got stuck. Checking stacks of the system_server
can help in figuring out the reason.

Bug: 135763139
Test: adb shell dumpsys audio
Change-Id: I02009720668af218edb38d5a5948a5964b72c685

services/core/java/com/android/server/audio/AudioService.java

@@ -127,6 +127,7 @@ import android.util.AndroidRuntimeException;
 import android.util.IntArray;
 import android.util.Log;
 import android.util.MathUtils;
+import android.util.PrintWriterPrinter;
 import android.util.Slog;
 import android.util.SparseIntArray;
 import android.view.KeyEvent;
@@ -6379,6 +6380,12 @@ public class AudioService extends IAudioService.Stub
     protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
         if (!DumpUtils.checkDumpPermission(mContext, TAG, pw)) return;
 
+        if (mAudioHandler != null) {
+            pw.println("\nMessage handler (watch for unhandled messages):");
+            mAudioHandler.dump(new PrintWriterPrinter(pw), "  ");
+        } else {
+            pw.println("\nMessage handler is null");
+        }
         mMediaFocusControl.dump(pw);
         dumpStreamStates(pw);
         dumpRingerMode(pw);