Basic DHCP framework and DHCPCD proxies.

DHCPProvider singleton will instantiate and supply DHCPConfig objects. Each
DHCPConfig object corresponds to a separate DHCP client (dhcpcd). Each
DHCPConfig object will be associated with a single DHCPCDProxy object to
communicate with that client. DHCPProvider will use a DHCPCDListener singleton
to figure the D-Bus destination of each spawned DHCP client dispatch signals to
its DHCPCDProxy.

Also fix dhcpcd.xml (this needs to be fixed in dhcpcd itself, really).

BUG=chromium-os:16013
TEST=manual by modifying shill_main and instantiating the proxies.

Change-Id: I8fb0eadb8c751365997db2ed2bdfde0711c362a3
Reviewed-on: http://gerrit.chromium.org/gerrit/1934
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
diff --git a/dhcp_provider.cc b/dhcp_provider.cc
new file mode 100644
index 0000000..abb97bd
--- /dev/null
+++ b/dhcp_provider.cc
@@ -0,0 +1,23 @@
+// 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.
+
+#include "shill/dhcp_provider.h"
+
+#include <base/logging.h>
+
+namespace shill {
+
+DHCPProvider::DHCPProvider() {
+  VLOG(2) << "DHCPProvider created.";
+}
+
+DHCPProvider::~DHCPProvider() {
+  VLOG(2) << "DHCPProvider destroyed.";
+}
+
+DHCPProvider* DHCPProvider::GetInstance() {
+  return Singleton<DHCPProvider>::get();
+}
+
+}  // namespace shill