[DRUEL01] Add DnsResolverUnsolicitedEventListener

Add DnsResolverUnsolicitedEventListener that can register
unsolicited event listener to get some dns resolver info.

Bug: 173485754
Test: atest resolv_integration_test resolv_unit_test\
      resolv_stress_test resolv_stats_test_utils_test
Change-Id: I5c229b3f23d5779f289d72f622b3c894780bc417
diff --git a/Android.bp b/Android.bp
index ce4d37f..8969886 100644
--- a/Android.bp
+++ b/Android.bp
@@ -27,6 +27,8 @@
         "binder/android/net/ResolverHostsParcel.aidl",
         "binder/android/net/ResolverOptionsParcel.aidl",
         "binder/android/net/ResolverParamsParcel.aidl",
+        // New AIDL classes should go into android.net.resolv.aidl so they can be clearly identified
+        "binder/android/net/resolv/aidl/**/*.aidl",
     ],
     imports: [
         "netd_event_listener_interface",
@@ -54,6 +56,7 @@
         "4",
         "5",
         "6",
+        "7",
     ],
 }