reland 31875. Revert was:...

base/file_util.h

 // 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.
 
 // This file contains utility functions for dealing with the local
 // filesystem.
 
 #ifndef BASE_FILE_UTIL_H_
 #define BASE_FILE_UTIL_H_
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #elif defined(OS_POSIX)
 #include <sys/stat.h>
 #endif
 
 #include <stdio.h>
 
 #include <stack>
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/file_path.h"
+#include "base/platform_file.h"
 #include "base/scoped_ptr.h"
 #include "base/string16.h"
 #include "base/time.h"
 
 #if defined(OS_POSIX)
 #include "base/file_descriptor_posix.h"
 #endif
 
 namespace base {
 class Time;
@@ skipping 446 matching lines @@
   // The default constructor sets all members to invalid/null values.
   MemoryMappedFile();
   ~MemoryMappedFile();
 
   // Opens an existing file and maps it into memory. Access is restricted to
   // read only. If this object already points to a valid memory mapped file
   // then this method will fail and return false. If it cannot open the file,
   // the file does not exist, or the memory mapping fails, it will return false.
   // Later we may want to allow the user to specify access.
   bool Initialize(const FilePath& file_name);
-#if defined(OS_POSIX)
-  // As above, but works with an alreay-opened file.
-  bool Initialize(const base::FileDescriptor& fd);
-#endif
+  // As above, but works with an already-opened file. MemoryMappedFile will take
+  // ownership of |file| and close it when done.
+  bool Initialize(base::PlatformFile file);
 
   const uint8* data() const { return data_; }
   size_t length() const { return length_; }
 
   // Is file_ a valid file handle that points to an open, memory mapped file?
   bool IsValid();
 
  private:
+  // Open the given file and pass it to MapFileToMemoryInternal().
+  bool MapFileToMemory(const FilePath& file_name);
+
   // Map the file to memory, set data_ to that memory address. Return true on
   // success, false on any kind of failure. This is a helper for Initialize().
-  bool MapFileToMemory(const FilePath& file_name);
-
-#if defined(OS_POSIX)
   bool MapFileToMemoryInternal();
-#endif
 
   // Closes all open handles. Later we may want to make this public.
   void CloseHandles();
 
+  base::PlatformFile file_;
 #if defined(OS_WIN)
-  HANDLE file_;
   HANDLE file_mapping_;
-#elif defined(OS_POSIX)
-  // The file descriptor.
-  base::FileDescriptor file_;
 #endif
   uint8* data_;
   size_t length_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
 };
 
 // Renames a file using the SHFileOperation API to ensure that the target file
 // gets the correct default security descriptor in the new path.
 bool RenameFileAndResetSecurityDescriptor(
     const FilePath& source_file_path,
     const FilePath& target_file_path);
 
 }  // namespace file_util
 
 #endif  // BASE_FILE_UTIL_H_