Make remaining parts of components/metrics use metrics namespace.

components/metrics/net/wifi_access_point_info_provider.cc

Index: components/metrics/net/wifi_access_point_info_provider.cc
diff --git a/components/metrics/net/wifi_access_point_info_provider.cc b/components/metrics/net/wifi_access_point_info_provider.cc
index c8f07a4505601e5c12b04b9a699b5823325f2360..21e04b181d25fc77de79bf18ed77d9eea6e267f8 100644
--- a/components/metrics/net/wifi_access_point_info_provider.cc
+++ b/components/metrics/net/wifi_access_point_info_provider.cc
@@ -4,6 +4,8 @@
 
 #include "components/metrics/net/wifi_access_point_info_provider.h"
 
+namespace metrics {
+
 WifiAccessPointInfoProvider::WifiAccessPointInfo::WifiAccessPointInfo() {
 }
 
@@ -19,3 +21,5 @@ WifiAccessPointInfoProvider::~WifiAccessPointInfoProvider() {
 bool WifiAccessPointInfoProvider::GetInfo(WifiAccessPointInfo *info) {
   return false;
 }
+
+}  // namespace metrics