Adds support for USB audio devices in AppRTCMobile on Android

webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java

Index: webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java
diff --git a/webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java b/webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java
index a57e84f8ca0aa81ed8ba6596ec3831e16667044d..992d9188ba9881dd7492ea675957a1deb5c87421 100644
--- a/webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java
+++ b/webrtc/examples/androidapp/src/org/appspot/apprtc/AppRTCAudioManager.java
@@ -18,7 +18,9 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
+import android.media.AudioDeviceInfo;
 import android.media.AudioManager;
+import android.os.Build;
 import android.preference.PreferenceManager;
 import android.util.Log;
 
@@ -437,7 +439,25 @@ public class AppRTCAudioManager {
    */
   @Deprecated
   private boolean hasWiredHeadset() {
-    return audioManager.isWiredHeadsetOn();
+    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
+      return audioManager.isWiredHeadsetOn();
+    } else {
+      final AudioDeviceInfo[] devices = audioManager.getDevices(AudioManager.GET_DEVICES_ALL);
+      for (AudioDeviceInfo device : devices) {
+        final int type = device.getType();
+        if (type == AudioDeviceInfo.TYPE_WIRED_HEADSET) {
+          Log.d(TAG, "hasWiredHeadset: found wired headset");
+          return true;
+        } else if (type == AudioDeviceInfo.TYPE_USB_DEVICE) {
+          Log.d(TAG, "hasWiredHeadset: found USB audio device");
+          return true;
+        } else if (type == AudioDeviceInfo.TYPE_USB_HEADSET) {
+          Log.d(TAG, "hasWiredHeadset: found USB headset");
+          return true;
+        }
+      }
+      return false;
+    }
   }
 
   /**