diff -r 000000000000 -r 6474c204b198 xpcom/threads/nsEnvironment.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xpcom/threads/nsEnvironment.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,34 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsEnvironment_h__
+#define nsEnvironment_h__
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Mutex.h"
+#include "nsIEnvironment.h"
+
+#define NS_ENVIRONMENT_CID \
+  { 0X3D68F92UL, 0X9513, 0X4E25, \
+  { 0X9B, 0XE9, 0X7C, 0XB2, 0X39, 0X87, 0X41, 0X72 } }
+#define NS_ENVIRONMENT_CONTRACTID "@mozilla.org/process/environment;1"
+
+class nsEnvironment MOZ_FINAL : public nsIEnvironment
+{
+public:
+    NS_DECL_THREADSAFE_ISUPPORTS
+    NS_DECL_NSIENVIRONMENT
+
+    static nsresult Create(nsISupports *aOuter, REFNSIID aIID,
+                           void **aResult);
+
+private:
+    nsEnvironment() : mLock("nsEnvironment.mLock") { }
+    ~nsEnvironment();
+
+    mozilla::Mutex mLock;
+};
+
+#endif /* !nsEnvironment_h__ */