a step toward enforcing unique metrics log IDs

First of several change lists:
1. Add in the new proto (this CL)
2. Migrate the existing code over to the proto.
3. Remove MetricsConstants once it is unused.

Bug: 26442178
Change-Id: Ic24829246af8ec5b202e39a85960aac5cf336c33
diff --git a/packages/SystemUI/Android.mk b/packages/SystemUI/Android.mk
index 61cad2f..e4d0fec 100644
--- a/packages/SystemUI/Android.mk
+++ b/packages/SystemUI/Android.mk
@@ -11,7 +11,8 @@
     android-support-v7-recyclerview \
     android-support-v7-preference \
     android-support-v7-appcompat \
-    android-support-v14-preference
+    android-support-v14-preference \
+    framework-protos
 
 LOCAL_JAVA_LIBRARIES := telephony-common