diff -r 000000000000 -r 6474c204b198 dom/quota/UsageInfo.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/quota/UsageInfo.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,82 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* 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 mozilla_dom_quota_usageinfo_h__
+#define mozilla_dom_quota_usageinfo_h__
+
+#include "mozilla/dom/quota/QuotaCommon.h"
+
+#include "mozilla/Atomics.h"
+#include "Utilities.h"
+
+BEGIN_QUOTA_NAMESPACE
+
+class UsageInfo
+{
+public:
+  UsageInfo()
+  : mCanceled(false), mDatabaseUsage(0), mFileUsage(0)
+  { }
+
+  virtual ~UsageInfo()
+  { }
+
+  bool
+  Canceled()
+  {
+    return mCanceled;
+  }
+
+  void
+  AppendToDatabaseUsage(uint64_t aUsage)
+  {
+    IncrementUsage(&mDatabaseUsage, aUsage);
+  }
+
+  void
+  AppendToFileUsage(uint64_t aUsage)
+  {
+    IncrementUsage(&mFileUsage, aUsage);
+  }
+
+  uint64_t
+  DatabaseUsage()
+  {
+    return mDatabaseUsage;
+  }
+
+  uint64_t
+  FileUsage()
+  {
+    return mFileUsage;
+  }
+
+  uint64_t
+  TotalUsage()
+  {
+    uint64_t totalUsage = mDatabaseUsage;
+    IncrementUsage(&totalUsage, mFileUsage);
+    return totalUsage;
+  }
+
+  void
+  ResetUsage()
+  {
+    mDatabaseUsage = 0;
+    mFileUsage = 0;
+  }
+
+protected:
+  mozilla::Atomic<bool> mCanceled;
+
+private:
+  uint64_t mDatabaseUsage;
+  uint64_t mFileUsage;
+};
+
+END_QUOTA_NAMESPACE
+
+#endif // mozilla_dom_quota_usageinfo_h__