Migrate NetworkStack metrics off StatsLog.write

Now that the new metrics API can be used, NetworkStack
metrics need to migrate off the legacy StatsLog.write.

Bug: 130323000
Test: Test with ./out/host/linux-x86/bin/statsd_testdrive 121
      to ensure log properly
Test: Ensure NetworkStackStatsLog will be generated as expected
Test: atest NetworkStackTest

cherry-picking commit e512b269132.

Change-Id: I8c70503cf1d9f1d06f30a1936d2d88857d0cff53
Merged-In: I1bfe856d771bf56fe33790aea22eceae2001921a
diff --git a/Android.bp b/Android.bp
index 5817118..e0bb862 100644
--- a/Android.bp
+++ b/Android.bp
@@ -37,6 +37,7 @@
         "src/**/*.java",
         ":framework-networkstack-shared-srcs",
         ":services-networkstack-shared-srcs",
+        ":statslog-networkstack-java-gen",
     ],
     static_libs: [
         "androidx.annotation_annotation",
@@ -104,3 +105,11 @@
     certificate: "networkstack",
     manifest: "AndroidManifest.xml",
 }
+
+genrule {
+    name: "statslog-networkstack-java-gen",
+    tools: ["stats-log-api-gen"],
+    cmd: "$(location stats-log-api-gen) --java $(out) --module network_stack" +
+         " --javaPackage com.android.networkstack.metrics --javaClass NetworkStackStatsLog",
+    out: ["com/android/networkstack/metrics/NetworkStackStatsLog.java"],
+}