Add net::SourceStream and net::FilterSourceStream

net/filter/source_stream.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef NET_CERT_OCSP_REVOCATION_STATUS_H
-#define NET_CERT_OCSP_REVOCATION_STATUS_H
+#include "net/filter/source_stream.h"
 
 namespace net {
 
-enum class OCSPRevocationStatus {
-  GOOD,
-  REVOKED,
-  UNKNOWN,
-};
+SourceStream::SourceStream(SourceType type) : type_(type) {}
+
+SourceStream::~SourceStream() {}
+
+std::string SourceStream::Description() const {
+  return "";
+}
 
 }  // namespace net
-
-#endif  // NET_CERT_OCSP_REVOCATION_STATUS_H