Remove more instances of guava optional for built in optional.

Test: tap
PiperOrigin-RevId: 202663404
Change-Id: Ic229d77f8f14bb9e60e82889ed5788dee600e957
diff --git a/java/com/android/incallui/InCallActivity.java b/java/com/android/incallui/InCallActivity.java
index 9db42d7..fa4a06e 100644
--- a/java/com/android/incallui/InCallActivity.java
+++ b/java/com/android/incallui/InCallActivity.java
@@ -96,12 +96,12 @@
 import com.android.incallui.video.protocol.VideoCallScreen;
 import com.android.incallui.video.protocol.VideoCallScreenDelegate;
 import com.android.incallui.video.protocol.VideoCallScreenDelegateFactory;
-import com.google.common.base.Optional;
 import com.google.common.util.concurrent.ListenableFuture;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Optional;
 
 /** Version of {@link InCallActivity} that shows the new UI */
 public class InCallActivity extends TransactionSafeFragmentActivity
@@ -124,7 +124,7 @@
   private static final int DIALPAD_REQUEST_SHOW = 2;
   private static final int DIALPAD_REQUEST_HIDE = 3;
 
-  private static Optional<Integer> audioRouteForTesting = Optional.absent();
+  private static Optional<Integer> audioRouteForTesting = Optional.empty();
 
   private SelectPhoneAccountListener selectPhoneAccountListener;
   private UiListener<Result> preferredAccountWorkerResultListener;