Makes AshTestImpl::Create create the right impl based on config

ash/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/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 
 # Historical note: Ash shipped on Windows for a couple years to support
@@ skipping 1074 matching lines @@
   ]
   configs += [
     "//build/config:precompiled_headers",
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 
   deps = [
     ":ash",
     ":ash_with_content",
     "//ash/public/cpp:ash_public_cpp",
-    "//ash/test:ash_with_aura_test_support",
     "//ash/test:test_support_with_content",
     "//base",
     "//base/test:test_support",
     "//chromeos",
     "//chromeos:power_manager_proto",
     "//chromeos:test_support_without_gmock",
     "//components/quirks",
     "//components/signin/core/account_id",
     "//components/user_manager",
     "//content/public/browser",
@@ skipping 296 matching lines @@
   ]
 
   deps = [
     ":ash",
     ":common_unittests",
     "//ash/autoclick/common:autoclick",
     "//ash/public/cpp:ash_public_cpp",
     "//ash/resources",
     "//ash/resources/vector_icons",
     "//ash/strings",
-    "//ash/test:ash_with_aura_test_support",
     "//ash/test:test_support_without_content",
     "//ash/touch_hud",
     "//base",
     "//base/test:test_support",
     "//chromeos",
     "//chromeos:test_support_without_gmock",
     "//components/quirks",
     "//components/signin/core/account_id",
     "//components/user_manager",
     "//device/bluetooth",
@@ skipping 69 matching lines @@
     "//content/public/app:both",
     "//device/bluetooth",
   ]
 
   data_deps = [
     "//ash/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_with_content_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 }