Using java_style enum generation for proto

This makes it easier to track various method parameters and simplifies
debug logging

Change-Id: Ib7c3d52590d0c36b2c8460c889ee3bead3454569
diff --git a/proguard.flags b/proguard.flags
index f1a3eaf..6cbab08 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -91,3 +91,6 @@
 #}
 -keep class android.support.v7.widget.RecyclerView { *; }
 
+-keep interface com.android.launcher3.userevent.nano.LauncherLogProto.** {
+  *;
+}