diff -r 000000000000 -r 6474c204b198 security/sandbox/chromium/base/threading/thread_local_storage.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/security/sandbox/chromium/base/threading/thread_local_storage.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,93 @@
+// Copyright (c) 2012 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 BASE_THREADING_THREAD_LOCAL_STORAGE_H_
+#define BASE_THREADING_THREAD_LOCAL_STORAGE_H_
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+
+#if defined(OS_POSIX)
+#include <pthread.h>
+#endif
+
+namespace base {
+
+// Wrapper for thread local storage.  This class doesn't do much except provide
+// an API for portability.
+class BASE_EXPORT ThreadLocalStorage {
+ public:
+
+  // Prototype for the TLS destructor function, which can be optionally used to
+  // cleanup thread local storage on thread exit.  'value' is the data that is
+  // stored in thread local storage.
+  typedef void (*TLSDestructorFunc)(void* value);
+
+  // StaticSlot uses its own struct initializer-list style static
+  // initialization, as base's LINKER_INITIALIZED requires a constructor and on
+  // some compilers (notably gcc 4.4) this still ends up needing runtime
+  // initialization.
+  #define TLS_INITIALIZER {0}
+
+  // A key representing one value stored in TLS.
+  // Initialize like
+  //   ThreadLocalStorage::StaticSlot my_slot = TLS_INITIALIZER;
+  // If you're not using a static variable, use the convenience class
+  // ThreadLocalStorage::Slot (below) instead.
+  struct BASE_EXPORT StaticSlot {
+    // Set up the TLS slot.  Called by the constructor.
+    // 'destructor' is a pointer to a function to perform per-thread cleanup of
+    // this object.  If set to NULL, no cleanup is done for this TLS slot.
+    // Returns false on error.
+    bool Initialize(TLSDestructorFunc destructor);
+
+    // Free a previously allocated TLS 'slot'.
+    // If a destructor was set for this slot, removes
+    // the destructor so that remaining threads exiting
+    // will not free data.
+    void Free();
+
+    // Get the thread-local value stored in slot 'slot'.
+    // Values are guaranteed to initially be zero.
+    void* Get() const;
+
+    // Set the thread-local value stored in slot 'slot' to
+    // value 'value'.
+    void Set(void* value);
+
+    bool initialized() const { return initialized_; }
+
+    // The internals of this struct should be considered private.
+    bool initialized_;
+#if defined(OS_WIN)
+    int slot_;
+#elif defined(OS_POSIX)
+    pthread_key_t key_;
+#endif
+
+  };
+
+  // A convenience wrapper around StaticSlot with a constructor. Can be used
+  // as a member variable.
+  class BASE_EXPORT Slot : public StaticSlot {
+   public:
+    // Calls StaticSlot::Initialize().
+    explicit Slot(TLSDestructorFunc destructor = NULL);
+
+   private:
+    using StaticSlot::initialized_;
+#if defined(OS_WIN)
+    using StaticSlot::slot_;
+#elif defined(OS_POSIX)
+    using StaticSlot::key_;
+#endif
+    DISALLOW_COPY_AND_ASSIGN(Slot);
+  };
+
+  DISALLOW_COPY_AND_ASSIGN(ThreadLocalStorage);
+};
+
+}  // namespace base
+
+#endif  // BASE_THREADING_THREAD_LOCAL_STORAGE_H_