diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/base/lock_impl_posix.cc
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/base/lock_impl_posix.cc	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,48 @@
+// 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.
+
+#include "base/lock_impl.h"
+
+#include <errno.h>
+
+#include "base/logging.h"
+
+LockImpl::LockImpl() {
+#ifndef NDEBUG
+  // In debug, setup attributes for lock error checking.
+  pthread_mutexattr_t mta;
+  int rv = pthread_mutexattr_init(&mta);
+  DCHECK_EQ(rv, 0);
+  rv = pthread_mutexattr_settype(&mta, PTHREAD_MUTEX_ERRORCHECK);
+  DCHECK_EQ(rv, 0);
+  rv = pthread_mutex_init(&os_lock_, &mta);
+  DCHECK_EQ(rv, 0);
+  rv = pthread_mutexattr_destroy(&mta);
+  DCHECK_EQ(rv, 0);
+#else
+  // In release, go with the default lock attributes.
+  pthread_mutex_init(&os_lock_, NULL);
+#endif
+}
+
+LockImpl::~LockImpl() {
+  int rv = pthread_mutex_destroy(&os_lock_);
+  DCHECK_EQ(rv, 0);
+}
+
+bool LockImpl::Try() {
+  int rv = pthread_mutex_trylock(&os_lock_);
+  DCHECK(rv == 0 || rv == EBUSY);
+  return rv == 0;
+}
+
+void LockImpl::Lock() {
+  int rv = pthread_mutex_lock(&os_lock_);
+  DCHECK_EQ(rv, 0);
+}
+
+void LockImpl::Unlock() {
+  int rv = pthread_mutex_unlock(&os_lock_);
+  DCHECK_EQ(rv, 0);
+}