Messaging: Language cleanup

No unnecessary boxing, enhanced for loops, redundant checks and throws,
imports (removal, reordering), possible void returns

Change-Id: I7a8e1b2007e3b0906e01b41785c518d02c2f3fab

src/com/android/messaging/util/NotificationPlayer.java

@@ -31,6 +31,7 @@ import androidx.annotation.NonNull;
 import com.android.messaging.Factory;
 
 import java.util.LinkedList;
+import java.util.Objects;
 
 /**
  * This class is provides the same interface and functionality as android.media.AsyncPlayer
@@ -257,11 +258,7 @@ public class NotificationPlayer implements OnCompletionListener {
      * @param tag a string to use for debugging
      */
     public NotificationPlayer(final String tag) {
-        if (tag != null) {
-            mTag = tag;
-        } else {
-            mTag = "NotificationPlayer";
-        }
+        mTag = Objects.requireNonNullElse(tag, "NotificationPlayer");
     }
 
     /**