diff -r 000000000000 -r 6474c204b198 toolkit/components/diskspacewatcher/DiskSpaceWatcher.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/diskspacewatcher/DiskSpaceWatcher.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,32 @@
+/* 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 __DISKSPACEWATCHER_H__
+
+#include "nsIDiskSpaceWatcher.h"
+#include "nsIObserver.h"
+#include "nsCOMPtr.h"
+
+class DiskSpaceWatcher MOZ_FINAL : public nsIDiskSpaceWatcher,
+                                   public nsIObserver
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIDISKSPACEWATCHER
+  NS_DECL_NSIOBSERVER
+
+  static already_AddRefed<DiskSpaceWatcher>
+  FactoryCreate();
+
+  static void UpdateState(bool aIsDiskFull, uint64_t aFreeSpace);
+
+private:
+  DiskSpaceWatcher();
+  ~DiskSpaceWatcher();
+
+  static uint64_t sFreeSpace;
+  static bool     sIsDiskFull;
+};
+
+#endif // __DISKSPACEWATCHER_H__