reland 31875. Revert was:...

base/file_util_win.cc

 // Copyright (c) 2006-2008 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.
 
 #include "base/file_util.h"
 
 #include <windows.h>
 #include <shellapi.h>
 #include <shlobj.h>
 #include <time.h>
@@ skipping 755 matching lines @@
 ///////////////////////////////////////////////
 // MemoryMappedFile
 
 MemoryMappedFile::MemoryMappedFile()
     : file_(INVALID_HANDLE_VALUE),
       file_mapping_(INVALID_HANDLE_VALUE),
       data_(NULL),
       length_(INVALID_FILE_SIZE) {
 }
 
-bool MemoryMappedFile::MapFileToMemory(const FilePath& file_name) {
-  file_ = ::CreateFile(file_name.value().c_str(), GENERIC_READ,
-                       FILE_SHARE_READ, NULL, OPEN_EXISTING,
-                       FILE_ATTRIBUTE_NORMAL, NULL);
+bool MemoryMappedFile::MapFileToMemoryInternal() {
   if (file_ == INVALID_HANDLE_VALUE)
     return false;
 
   length_ = ::GetFileSize(file_, NULL);
   if (length_ == INVALID_FILE_SIZE)
     return false;
 
   file_mapping_ = ::CreateFileMapping(file_, NULL, PAGE_READONLY,
                                       0, length_, NULL);
   if (file_mapping_ == INVALID_HANDLE_VALUE)
@@ skipping 11 matching lines @@
     ::CloseHandle(file_mapping_);
   if (file_ != INVALID_HANDLE_VALUE)
     ::CloseHandle(file_);
 
   data_ = NULL;
   file_mapping_ = file_ = INVALID_HANDLE_VALUE;
   length_ = INVALID_FILE_SIZE;
 }
 
 }  // namespace file_util