Make remaining parts of components/metrics use metrics namespace.

components/metrics/net/wifi_access_point_info_provider_chromeos.cc

Index: components/metrics/net/wifi_access_point_info_provider_chromeos.cc
diff --git a/components/metrics/net/wifi_access_point_info_provider_chromeos.cc b/components/metrics/net/wifi_access_point_info_provider_chromeos.cc
index c05829b014793c41993495acd6e480b22021378e..314ddc546a414860e282aee158a91012e111fd18 100644
--- a/components/metrics/net/wifi_access_point_info_provider_chromeos.cc
+++ b/components/metrics/net/wifi_access_point_info_provider_chromeos.cc
@@ -16,6 +16,8 @@
 
 using chromeos::NetworkHandler;
 
+namespace metrics {
+
 WifiAccessPointInfoProviderChromeos::WifiAccessPointInfoProviderChromeos() {
   NetworkHandler::Get()->network_state_handler()->AddObserver(this, FROM_HERE);
 
@@ -116,3 +118,5 @@ void WifiAccessPointInfoProviderChromeos::ParseInfo(
   vendor_dict->GetStringWithoutPathExpansion(shill::kVendorOUIListProperty,
                                              &wifi_access_point_info_.oui_list);
 }
+
+}  // namespace metrics