Move WriteFile and WriteFileDescriptor from file_util to base namespace.

net/http/transport_security_persister_unittest.cc

Index: net/http/transport_security_persister_unittest.cc
diff --git a/net/http/transport_security_persister_unittest.cc b/net/http/transport_security_persister_unittest.cc
index 8c41f9e81daad844049fcef091eea1fcb38b4852..114e933bde4db0e94abc74f851d5b2e1c2eb804d 100644
--- a/net/http/transport_security_persister_unittest.cc
+++ b/net/http/transport_security_persister_unittest.cc
@@ -127,8 +127,7 @@ TEST_F(TransportSecurityPersisterTest, SerializeData3) {
   // than block.) Use a different basename just for cleanliness.
   base::FilePath path =
       temp_dir_.path().AppendASCII("TransportSecurityPersisterTest");
-  EXPECT_TRUE(file_util::WriteFile(path, serialized.c_str(),
-                                   serialized.size()));
+  EXPECT_TRUE(base::WriteFile(path, serialized.c_str(), serialized.size()));
 
   // Read the data back.
   std::string persisted;