Move mute/unmute handling to adjust volume paths

This deprecates the setStreamMute and setStreamSolo APIs. Soloing is no
longer supported and muting is redirected through the adjust volume APIs.

Also updates the hidden master versions of these APIs.

Change-Id: I65d2a5d5fc15b386bd497abf8ca6869fec75a26a
diff --git a/core/java/android/bluetooth/BluetoothA2dp.java b/core/java/android/bluetooth/BluetoothA2dp.java
index 0450150..767f59e 100644
--- a/core/java/android/bluetooth/BluetoothA2dp.java
+++ b/core/java/android/bluetooth/BluetoothA2dp.java
@@ -22,6 +22,7 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.ServiceConnection;
+import android.media.AudioManager;
 import android.os.IBinder;
 import android.os.ParcelUuid;
 import android.os.RemoteException;
@@ -415,9 +416,16 @@
     }
 
     /**
-     * Tells remote device to adjust volume. Only if absolute volume is supported.
+     * Tells remote device to adjust volume. Only if absolute volume is
+     * supported. Uses the following values:
+     * <ul>
+     * <li>{@link AudioManager#ADJUST_LOWER}</li>
+     * <li>{@link AudioManager#ADJUST_RAISE}</li>
+     * <li>{@link AudioManager#ADJUST_MUTE}</li>
+     * <li>{@link AudioManager#ADJUST_UNMUTE}</li>
+     * </ul>
      *
-     * @param direction 1 to increase volume, or -1 to decrease volume
+     * @param direction One of the supported adjust values.
      * @hide
      */
     public void adjustAvrcpAbsoluteVolume(int direction) {