diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/base/hmac.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/base/hmac.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,56 @@
+// Copyright (c) 2006-2008 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.
+
+// Utility class for calculating the HMAC for a given message. We currently
+// only support SHA1 for the hash algorithm, but this can be extended easily.
+
+#ifndef BASE_HMAC_H_
+#define BASE_HMAC_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/scoped_ptr.h"
+
+namespace base {
+
+// Simplify the interface and reduce includes by abstracting out the internals.
+struct HMACPlatformData;
+
+class HMAC {
+ public:
+  // The set of supported hash functions. Extend as required.
+  enum HashAlgorithm {
+    SHA1
+  };
+
+  explicit HMAC(HashAlgorithm hash_alg);
+  ~HMAC();
+
+  // Initializes this instance using |key| of the length |key_length|. Call Init
+  // only once. It returns false on the second or later calls.
+  bool Init(const unsigned char* key, int key_length);
+
+  // Initializes this instance using |key|. Call Init only once. It returns
+  // false on the second or later calls.
+  bool Init(const std::string& key) {
+    return Init(reinterpret_cast<const unsigned char*>(key.data()),
+                static_cast<int>(key.size()));
+  }
+
+  // Calculates the HMAC for the message in |data| using the algorithm supplied
+  // to the constructor and the key supplied to the Init method. The HMAC is
+  // returned in |digest|, which has |digest_length| bytes of storage available.
+  bool Sign(const std::string& data, unsigned char* digest, int digest_length);
+
+ private:
+  HashAlgorithm hash_alg_;
+  scoped_ptr<HMACPlatformData> plat_;
+
+  DISALLOW_COPY_AND_ASSIGN(HMAC);
+};
+
+}  // namespace base
+
+#endif  // BASE_HMAC_H_