Extracts InterfaceRegistry from ConnectionImpl.

mojo/shell/public/cpp/tests/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.
 
 import("//testing/test.gni")
 
 test("mojo_public_application_unittests") {
   sources = [
-    "connection_impl_unittest.cc",
+    "interface_registry_unittest.cc",
   ]
 
   deps = [
     "//base",
     "//mojo/edk/test:run_all_unittests",
     "//mojo/shell/public/cpp",
     "//testing/gtest",
   ]
 }