Add mach ports support to the Mojo shell.

mojo/shell/runner/host/mach_broker.cc

Index: mojo/shell/runner/host/mach_broker.cc
diff --git a/mojo/shell/runner/host/mach_broker.cc b/mojo/shell/runner/host/mach_broker.cc
new file mode 100644
index 0000000000000000000000000000000000000000..8b992793a4e3768070a6fcf5af83e241d00999a5
--- /dev/null
+++ b/mojo/shell/runner/host/mach_broker.cc
@@ -0,0 +1,45 @@
+// 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.
+
+#include "mojo/shell/runner/host/mach_broker.h"
+
+#include "base/logging.h"
+#include "base/memory/singleton.h"
+
+namespace mojo {
+namespace shell {
+
+namespace {
+const char kBootstrapPortName[] = "mojo_shell";
+}
+
+// static
+void MachBroker::SendTaskPortToParent() {
+  bool result = base::MachPortBroker::ChildSendTaskPortToParent(
+      kBootstrapPortName);
+  DCHECK(result);
+}
+
+// static
+MachBroker* MachBroker::GetInstance() {
+  return base::Singleton<MachBroker>::get();
+}
+
+MachBroker::MachBroker() : broker_(kBootstrapPortName) {
+  bool result = broker_.Init();
+  DCHECK(result);
+}
+
+MachBroker::~MachBroker() {}
+
+void MachBroker::ExpectPid(base::ProcessHandle pid) {
+  broker_.AddPlaceholderForPid(pid);
+}
+
+void MachBroker::RemovePid(base::ProcessHandle pid) {
+  broker_.InvalidatePid(pid);
+}
+
+}  // namespace shell
+}  // namespace mojo