diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/base/hmac_mac.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/base/hmac_mac.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,69 @@
+// Copyright (c) 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.
+
+#include "base/hmac.h"
+
+#include <CommonCrypto/CommonHMAC.h>
+
+#include "base/logging.h"
+
+namespace base {
+
+struct HMACPlatformData {
+  std::string key_;
+};
+
+HMAC::HMAC(HashAlgorithm hash_alg)
+    : hash_alg_(hash_alg), plat_(new HMACPlatformData()) {
+  // Only SHA-1 digest is supported now.
+  DCHECK(hash_alg_ == SHA1);
+}
+
+bool HMAC::Init(const unsigned char *key, int key_length) {
+  if (!plat_->key_.empty()) {
+    // Init must not be called more than once on the same HMAC object.
+    NOTREACHED();
+    return false;
+  }
+
+  plat_->key_.assign(reinterpret_cast<const char*>(key), key_length);
+
+  return true;
+}
+
+HMAC::~HMAC() {
+  // Zero out key copy.
+  plat_->key_.assign(plat_->key_.length(), std::string::value_type());
+  plat_->key_.clear();
+  plat_->key_.reserve(0);
+}
+
+bool HMAC::Sign(const std::string& data,
+                unsigned char* digest,
+                int digest_length) {
+  CCHmacAlgorithm algorithm;
+  int algorithm_digest_length;
+  switch (hash_alg_) {
+    case SHA1:
+      algorithm = kCCHmacAlgSHA1;
+      algorithm_digest_length = CC_SHA1_DIGEST_LENGTH;
+      break;
+    default:
+      NOTREACHED();
+      return false;
+  }
+
+  if (digest_length < algorithm_digest_length) {
+    NOTREACHED();
+    return false;
+  }
+
+  CCHmac(algorithm,
+         plat_->key_.data(), plat_->key_.length(), data.data(), data.length(),
+         digest);
+
+  return true;
+}
+
+}  // namespace base