Move the test template to //testing/test.gni (part 2)

ui/shell_dialogs/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("//build/config/ui.gni")
+import("//testing/rules.gni")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 component("shell_dialogs") {
   sources = [
     "android/shell_dialogs_jni_registrar.cc",
     "android/shell_dialogs_jni_registrar.h",
     "base_shell_dialog.cc",
     "base_shell_dialog.h",
@@ skipping 56 matching lines @@
   ]
 
   deps = [
     ":shell_dialogs",
     "//base",
     "//base/test:test_support",
     "//base/test:run_all_unittests",
     "//testing/gtest",
   ]
 }