Implement basic ShowItemInFolder for linux....

chrome/common/platform_util.h

Index: chrome/common/platform_util.h
===================================================================
--- chrome/common/platform_util.h	(revision 0)
+++ chrome/common/platform_util.h	(revision 0)
@@ -0,0 +1,17 @@
+// 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_COMMON_PLATFORM_UTIL_H_
+#define CHROME_COMMON_PLATFORM_UTIL_H_
+
+class FilePath;
+
+namespace platform_util {
+
+// Show the given file in a file manager. If possible, select the file.
+void ShowItemInFolder(const FilePath& full_path);
+
+}
+
+#endif  // CHROME_COMMON_PLATFORM_UTIL_H_