Initial skeletal implementation of the PrincipalService. Also, use the Login()/GetUserBlessing()

services/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 group("services") {
   deps = [
     "//services/asset_bundle",
     "//services/authenticating_url_loader_interceptor",
     "//services/authentication",
     "//services/clipboard",
@@ skipping 22 matching lines @@
     deps += [
       "//services/android:java_handler",
       "//services/camera_roll",
       "//services/location",
       "//services/notifications",
       "//services/sensors",
       "//services/speech_recognizer",
     ]
   }
 
+  if (defined(go_build_tool) && go_build_tool != "") {
+    deps += [ "//services/vanadium/security:go_principal_service" ]
+  }
+
   if (is_linux) {
     deps += [ "//services/python" ]
   }
 
   # TODO(jamesr): We only support building V8 snapshot data on a linux host since it
   # needs a 32 bit toolchain and we don't have one configured for mac hosts.
   if (host_os == "linux") {
     deps += [ "//services/js" ]
   }
 }