shill: Move Metrics from singleton to Shill daemon

While implementing chromium-os:24810, it was discovered that Metrics is
cleaner if it is passed around like ControlInterface, Dispatcher,
Manager, etc.  This approach also makes Metrics more testable.

BUG=chromium-os:24810
TEST=Unit tests, network_WiFiManager suite

Change-Id: I556a1bd11f21f0b93ecfeaae8855dfb99ed5e5f9
Reviewed-on: https://gerrit.chromium.org/gerrit/14099
Commit-Ready: Thieu Le <thieule@chromium.org>
Reviewed-by: Thieu Le <thieule@chromium.org>
Tested-by: Thieu Le <thieule@chromium.org>
diff --git a/ethernet_service.h b/ethernet_service.h
index 2bdb945..6dbcf1b 100644
--- a/ethernet_service.h
+++ b/ethernet_service.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -16,11 +16,13 @@
 class ControlInterface;
 class EventDispatcher;
 class Manager;
+class Metrics;
 
 class EthernetService : public Service {
  public:
   EthernetService(ControlInterface *control_interface,
                   EventDispatcher *dispatcher,
+                  Metrics *metrics,
                   Manager *manager,
                   const EthernetRefPtr &device);
   ~EthernetService();