Implement basic classes for HPACK (HTTP/2 compression)

net/spdy/hpack_string_util.h

+// Copyright (c) 2014 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_SPDY_HPACK_STRING_UTIL_H_
+#define NET_SPDY_HPACK_STRING_UTIL_H_
+
+#include "base/strings/string_piece.h"
+#include "net/base/net_export.h"
+
+namespace net {
+
+// All section references below are to
+// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-04
+// .
+
+// A constant-time StringPiece comparison function, as suggested
+// by section 6.
+bool NET_EXPORT_PRIVATE StringPiecesEqualConstantTime(
+    base::StringPiece str1,
+    base::StringPiece str2);
+
+}  // namespace net
+
+#endif  // NET_SPDY_HPACK_STRING_UTIL_H_