Move Touch to base namespace, remove SetLastModifiedTime.

net/proxy/proxy_config_service_linux_unittest.cc

Index: net/proxy/proxy_config_service_linux_unittest.cc
diff --git a/net/proxy/proxy_config_service_linux_unittest.cc b/net/proxy/proxy_config_service_linux_unittest.cc
index c3a1aa5b9faa5c951f2a37009ca53c571ec51223..99a3b570b2520196a22d46f9263778ee6fe89ee7 100644
--- a/net/proxy/proxy_config_service_linux_unittest.cc
+++ b/net/proxy/proxy_config_service_linux_unittest.cc
@@ -1597,7 +1597,7 @@ TEST_F(ProxyConfigServiceLinuxTest, KDEHomePicker) {
 
   // Finally, make the .kde4 config directory older than the .kde directory
   // and make sure we then use .kde instead of .kde4 since it's newer.
-  file_util::SetLastModifiedTime(kde4_config_, base::Time());
+  base::TouchFile(kde4_config_, base::Time(), base::Time());
 
   { SCOPED_TRACE("KDE4, very old .kde4 directory present, use .kde");
     MockEnvironment* env = new MockEnvironment;