Add support for UserIdleTime to Linux.

chrome/browser/sync/engine/idle_query_linux.h

+// Copyright (c) 2009 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 CHROME_BROWSER_SYNC_ENGINE_IDLE_QUERY_LINUX_H_
+#define CHROME_BROWSER_SYNC_ENGINE_IDLE_QUERY_LINUX_H_
+
+#include "base/scoped_ptr.h"
+
+namespace browser_sync {
+
+class IdleData;
+
+class IdleQueryLinux {
+ public:
+  IdleQueryLinux();
+  ~IdleQueryLinux();
+  int IdleTime();
+
+ private:
+  scoped_ptr<IdleData> idle_data_;
+};
+
+}  // namespace browser_sync
+#endif  // CHROME_BROWSER_SYNC_ENGINE_IDLE_QUERY_LINUX_H_