shill: Ethernet: Detect EAP Requests

Launch an EAP listener when link appears, and use this to set a
read-only boolean device attribute.

BUG=chromium:225914
TEST=Ethernet unit test (finally).
Upcoming autotest at https://gerrit.chromium.org/gerrit/47272

Change-Id: I51fcf40ea2e21cc2c278a05e9db6b2660d3b920e
Reviewed-on: https://gerrit.chromium.org/gerrit/47270
Commit-Queue: Paul Stewart <pstew@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
diff --git a/mock_eap_listener.cc b/mock_eap_listener.cc
new file mode 100644
index 0000000..e738c29
--- /dev/null
+++ b/mock_eap_listener.cc
@@ -0,0 +1,13 @@
+// Copyright (c) 2013 The Chromium OS 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 "shill/mock_eap_listener.h"
+
+namespace shill {
+
+MockEapListener::MockEapListener() : EapListener(NULL, 0) {}
+
+MockEapListener::~MockEapListener() {}
+
+}  // namespace shill