Move gn _run target generation into test().

mojo/common/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")
 
 group("common") {
   public_deps = [
     ":common_base",
     ":url_type_converters",
@@ skipping 46 matching lines @@
 
   deps = [
     ":common_base",
     "//base",
     "//base/third_party/dynamic_annotations",
     "//mojo/public/cpp/bindings",
     "//url",
   ]
 }
 
-# TODO(GYP): Delete this after we've converted everything to GN.
-# The _run targets exist only for compatibility w/ GYP.
-group("mojo_common_unittests_run") {
-  testonly = true
-  deps = [
-    ":mojo_common_unittests",
-  ]
-}
-
 # GYP version: mojo/mojo_base.gyp:mojo_common_unittests
 test("mojo_common_unittests") {
   deps = [
     ":common",
     "//base",
     "//base:message_loop_tests",
     "//base/test:test_support",
     "//mojo/environment:chromium",
     "//mojo/message_pump",
     "//mojo/public/cpp/bindings",
@@ skipping 33 matching lines @@
   sources = [
     "../message_pump/handle_watcher_perftest.cc",
   ]
 
   if (is_linux && !is_component_build) {
     # This test dynamically loads libmojo_test_support even in non-component
     # builds.
     configs += [ "//build/config/gcc:rpath_for_built_shared_libraries" ]
   }
 }