[Mac/GN] Set up the component build.

components/test_runner/BUILD.gn

 # Copyright 2015 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")
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
@@ skipping 105 matching lines @@
     "//skia",
     "//third_party/WebKit/public:blink",
     "//ui/events:dom_keycode_converter",
     "//ui/events:events_base",
     "//ui/gfx",
     "//ui/gfx:test_support",
     "//ui/gfx/geometry",
     "//url",
     "//v8",
   ]
+
+  if (is_mac) {
+    libs = [ "AppKit.framework" ]
+  }
 }
 
 # Font copies.
 if (!is_mac) {
   copy("copy_ahem") {
     visibility = [ ":*" ]
     sources = [
       "resources/fonts/AHEM____.TTF",
     ]
     outputs = [
@@ skipping 67 matching lines @@
     if (is_mac) {
       libs = [ "AppKit.framework" ]
     }
 
     deps = [
       "//build/config/sanitizers:deps",
       "//build/win:default_exe_manifest",
     ]
   }
 }