Perform device discovery and registration in device_info

Also, do device classification, and create the beginnings of
Device subclasses for WiFi and Ethernet.

BUG=chromium-os:12933
TEST=Added unit tests.  Also manual on a testbed machine to confirm WiFi
device detection.

Change-Id: I48b8fa2b3b966b22acf80f693d9522bff0221884
Reviewed-on: http://gerrit.chromium.org/gerrit/1084
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
diff --git a/wifi.h b/wifi.h
new file mode 100644
index 0000000..33e29d8
--- /dev/null
+++ b/wifi.h
@@ -0,0 +1,29 @@
+// Copyright (c) 2011 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.
+
+#ifndef SHILL_WIFI_
+#define SHILL_WIFI_
+
+#include "shill/device.h"
+#include "shill/shill_event.h"
+
+namespace shill {
+
+// Device superclass.  Individual network interfaces types will inherit from
+// this class.
+class WiFi : public Device {
+ public:
+  explicit WiFi(ControlInterface *control_interface,
+                EventDispatcher *dispatcher,
+                const string &link_name,
+                int interface_index);
+  ~WiFi();
+  bool TechnologyIs(Device::Technology type);
+ private:
+  DISALLOW_COPY_AND_ASSIGN(WiFi);
+};
+
+}  // namespace shill
+
+#endif  // SHILL_WIFI_