Add a buffer reader/writer for NTLM.

net/BUILD.gn

Index: net/BUILD.gn
diff --git a/net/BUILD.gn b/net/BUILD.gn
index d55845cc3045998093bd78a7bfde83a22e0d2beb..df4d4507c0bedf6d3ce274de494fabc405067f08 100644
--- a/net/BUILD.gn
+++ b/net/BUILD.gn
@@ -285,6 +285,11 @@ component("net") {
     "http/http_util.h",
     "http/http_vary_data.cc",
     "http/http_vary_data.h",
+    "http/ntlm.h",
+    "http/ntlm_buffer_reader.cc",
+    "http/ntlm_buffer_reader.h",
+    "http/ntlm_buffer_writer.cc",
+    "http/ntlm_buffer_writer.h",
     "http/transport_security_state.cc",
     "http/transport_security_state.h",
     "http/transport_security_state_source.h",
@@ -4717,6 +4722,8 @@ test("net_unittests") {
     "http/mock_http_cache.h",
     "http/mock_sspi_library_win.cc",
     "http/mock_sspi_library_win.h",
+    "http/ntlm_buffer_reader_unittest.cc",
+    "http/ntlm_buffer_writer_unittest.cc",
     "http/transport_security_persister_unittest.cc",
     "http/transport_security_state_unittest.cc",
     "http/url_security_manager_unittest.cc",