Modify fileAtPath stat to track if the call was redirected by chrome_elf.

chrome_elf/create_file/chrome_create_file.h

 // Copyright 2014 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_ELF_CREATE_FILE_CHROME_CREATE_FILE_H_
 #define CHROME_ELF_CREATE_FILE_CHROME_CREATE_FILE_H_
 
 #include <windows.h>
 
 #include "chrome_elf/chrome_elf_types.h"
 
 // A CreateFileW replacement that will call NTCreateFile directly when the
 // criteria defined in ShouldBypass() are satisfied for |lp_file_name|.
 extern "C" HANDLE WINAPI CreateFileWRedirect(
     LPCWSTR file_name,
     DWORD desired_access,
     DWORD share_mode,
     LPSECURITY_ATTRIBUTES security_attributes,
     DWORD creation_disposition,
     DWORD flags_and_attributes,
     HANDLE template_file);
 
+// Returns the count of CreateFile calls redirected so far.
+extern "C" int GetRedirectCount();
+
 // Partial reimplementation of kernel32!CreateFile (very partial: only handles
 // reading and writing to files in the User Data directory).
 HANDLE CreateFileNTDLL(
     LPCWSTR file_name,
     DWORD desired_access,
     DWORD share_mode,
     LPSECURITY_ATTRIBUTES security_attributes,
     DWORD creation_disposition,
     DWORD flags_and_attributes,
     HANDLE template_file);
 
 // Determines whether or not we should use our version of CreateFile, or the
 // system version (only uses ours if we're writing to the user data directory).
 bool ShouldBypass(LPCWSTR file_name);
 
 #endif  // CHROME_ELF_CREATE_FILE_CHROME_CREATE_FILE_H_