Add mach ports support to the Mojo shell.

mojo/shell/runner/host/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("//mojo/public/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 group("host") {
   testonly = true
@@ skipping 81 matching lines @@
       "linux_sandbox.h",
     ]
 
     deps += [
       "//sandbox/linux:sandbox",
       "//sandbox/linux:sandbox_services",
       "//sandbox/linux:seccomp_bpf",
       "//sandbox/linux:seccomp_bpf_helpers",
     ]
   }
+
+  if (is_mac) {
+    sources += [
+      "mach_broker.cc",
+      "mach_broker.h",
+    ]
+  }
 }
 
 test("mojo_runner_host_unittests") {
   sources = [
     "child_process_host_unittest.cc",
     "host_unittests.cc",
     "in_process_native_runner_unittest.cc",
   ]
 
   deps = [
     ":lib",
     "//base",
     "//base/test:test_support",
     "//mojo/edk/system",
     "//mojo/message_pump",
     "//mojo/shell",
     "//mojo/shell/runner:init",
     "//mojo/shell/runner/common",
     "//testing/gtest",
   ]
 }