gcapi_mac: Add gn build file.

BUILD.gn

 # Copyright (c) 2013 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.
 
 # This is the root build file for GN. GN will start processing by loading this
 # file, and recursively load all dependencies until all dependencies are either
 # resolved or known not to exist (which will cause the build to fail). So if
 # you add a new build file, there must be some path of dependencies from this
 # file to your new one or GN won't know about it.
 
@@ skipping 239 matching lines @@
     deps += [ "//tools/xdisplaycheck" ]
   }
 
   if (is_win) {
     deps += [
       "//chrome/installer/gcapi",
       "//chrome/tools/build/win/syzygy:chrome_dll_syzygy",
     ]
   }
 
+  if (is_mac) {
+    deps += [ "//chrome/installer/gcapi_mac:gcapi_example" ]
+  }
+
   if (is_android) {
     deps += [
       "//base:base_junit_tests",
       "//base/android/linker:chromium_android_linker",
       "//build/android/gyp/test:hello_world",
       "//chrome/android/webapk/shell_apk:webapk",
       "//components/invalidation/impl:components_invalidation_impl_junit_tests",
       "//components/policy/android:components_policy_junit_tests",
       "//content/public/android:content_junit_tests",
       "//content/shell/android:content_shell_apk",
@@ skipping 822 matching lines @@
   assert(target_name != "")  # Mark as used.
   sources = invoker.actual_sources
   assert(
       sources == invoker.actual_sources,
       "Do not use a platform name in your output directory (found \"$root_build_dir\"). http://crbug.com/548283")
 }
 
 assert_valid_out_dir("_unused") {
   actual_sources = [ "$root_build_dir/foo" ]
 }