Introduce proximity_auth component.

components/proximity_auth/proximity_auth_system.cc

+// Copyright 2014 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 "components/proximity_auth/proximity_auth_system.h"
+
+namespace proximity_auth {
+
+ProximityAuthSystem::ProximityAuthSystem(const RemoteDeviceList& remote_devices)
+    : remote_devices_(remote_devices) {
+}
+
+ProximityAuthSystem::~ProximityAuthSystem() {
+}
+
+const RemoteDeviceList& ProximityAuthSystem::GetRemoteDevices() {
+  return remote_devices_;
+}
+
+}  // proximity_auth