Enable optimizer on service-connectivity

The optimizer has been enabled in downstream branches (including those
used for upcoming module releases) for a few months. This brings aosp in
line with them.

This is a cherry-pick of change:
I3be9422a431a5b5bc1478960ce332a89377bd632

where proguard.flags have been replaced with the most up-to-date version
used in downstream branches.

Test: m
Merged-In: I3be9422a431a5b5bc1478960ce332a89377bd632
Change-Id: I55455eb58d3fdc4dbf3ea81961d5c7756fea0046

service/Android.bp

@@ -216,6 +216,11 @@ java_library {
     apex_available: [
         "com.android.tethering",
     ],
+    optimize: {
+        enabled: true,
+        shrink: true,
+        proguard_flags_files: ["proguard.flags"],
+    },
     lint: { strict_updatability_linting: true },
 }
 

service/proguard.flags

@@ -0,0 +1,18 @@
+# Make sure proguard keeps all connectivity classes
+# TODO: instead of keeping everything, consider listing only "entry points"
+# (service loader, JNI registered methods, etc) and letting the optimizer do its job
+-keep class android.net.** { *; }
+-keep class com.android.connectivity.** { *; }
+-keep class com.android.net.** { *; }
+-keep class !com.android.server.nearby.**,com.android.server.** { *; }
+
+# Prevent proguard from stripping out any nearby-service and fast-pair-lite-protos fields.
+-keep class com.android.server.nearby.NearbyService { *; }
+-keep class com.android.server.nearby.service.proto { *; }
+
+# The lite proto runtime uses reflection to access fields based on the names in
+# the schema, keep all the fields.
+# This replicates the base proguard rule used by the build by default
+# (proguard_basic_keeps.flags), but needs to be specified here because the
+# com.google.protobuf package is jarjared to the below package.
+-keepclassmembers class * extends com.android.connectivity.com.google.protobuf.MessageLite { <fields>; }