base(Android.bp): Include BackupUtils in wifi shared srcs

Bug: 145685697
Test: Compiles
Change-Id: Ia937afead862b2220037b3c4846a88775d707f4f
diff --git a/Android.bp b/Android.bp
index a7ce917..412a8ec 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1675,6 +1675,7 @@
     srcs: [
         ":framework-annotations",
 	"core/java/android/os/HandlerExecutor.java",
+        "core/java/android/util/BackupUtils.java",
         "core/java/android/util/KeyValueListParser.java",
         "core/java/android/util/LocalLog.java",
         "core/java/android/util/Rational.java",