Retrieve client_id from GoogleUpdateSettings when its missing from Local State.

components/metrics/client_info.cc

Index: components/metrics/client_info.cc
diff --git a/components/metrics/client_info.cc b/components/metrics/client_info.cc
new file mode 100644
index 0000000000000000000000000000000000000000..57ad3947c1bd6b736b3acd2b3b15e20454f9f135
--- /dev/null
+++ b/components/metrics/client_info.cc
@@ -0,0 +1,13 @@
+// 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/metrics/client_info.h"
+
+namespace metrics {
+
+ClientInfo::ClientInfo() : installation_date(0), reporting_enabled_date(0) {}
+
+ClientInfo::~ClientInfo() {}
+
+}  // namespace metrics