Pre-import to remove a conflict.

Test: compiles and passes checkstyle
Change-Id: I1ffdd88e6268fee0cf88992420ab21eb42928957
diff --git a/core/java/android/net/NetworkCapabilities.java b/core/java/android/net/NetworkCapabilities.java
index be85583..6bcaffd 100644
--- a/core/java/android/net/NetworkCapabilities.java
+++ b/core/java/android/net/NetworkCapabilities.java
@@ -20,6 +20,7 @@
 import android.net.ConnectivityManager.NetworkCallback;
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.util.proto.ProtoOutputStream;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.BitUtils;