Convert some GN test support targets to static libs.

ui/app_list/presenter/BUILD.gn

 # Copyright 2016 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("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 assert(use_aura)
 
@@ skipping 28 matching lines @@
 
 mojom("mojom") {
   sources = [
     "app_list_presenter.mojom",
   ]
   deps = [
     "//services/ui/public/interfaces",
   ]
 }
 
-source_set("test_support") {
+static_library("test_support") {
   sources = [
     "test/app_list_presenter_impl_test_api.cc",
     "test/app_list_presenter_impl_test_api.h",
 
     # Temporary dependency to fix compile flake in http://crbug.com/611898.
     # TODO(tapted): Remove once http://crbug.com/612382 is fixed.
     "//ui/accessibility:ax_gen",
   ]
 
   public_deps = [
@@ skipping 27 matching lines @@
 
     # Temporary dependency to fix compile flake in http://crbug.com/611898.
     # TODO(tapted): Remove once http://crbug.com/612382 is fixed.
     "//ui/accessibility:ax_gen",
   ]
 
   data_deps = [
     "//ui/resources:ui_test_pak_data",
   ]
 }