Add data saver to settings

Bug: 22817899

Change-Id: Ic3055aa6a5baae1653db350313366f180c049cc7
diff --git a/proguard.flags b/proguard.flags
index 578ff4d..448cd72 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -5,6 +5,7 @@
 -keep class com.android.settings.wifi.*Settings
 -keep class com.android.settings.deviceinfo.*
 -keep class com.android.settings.bluetooth.*
+-keep class com.android.settings.datausage.*
 -keep class com.android.settings.applications.*
 -keep class com.android.settings.inputmethod.*
 -keep class com.android.settings.ResetNetwork