Convert base::MemoryMappedFile to use File instead of PlatformFile.

base/files/file.h

 // Copyright (c) 2012 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 BASE_FILES_FILE_H_
 #define BASE_FILES_FILE_H_
 
 #include "build/build_config.h"
 #if defined(OS_WIN)
 #include <windows.h>
@@ skipping 139 matching lines @@
   explicit File(PlatformFile platform_file);
 
   // Move constructor for C++03 move emulation of this type.
   File(RValue other);
 
   ~File();
 
   // Move operator= for C++03 move emulation of this type.
   File& operator=(RValue other);
 
+  // Creates or opens the given file.
+  void Initialize(const FilePath& name, uint32 flags);
+
   // Creates or opens the given file, allowing paths with traversal ('..')
   // components. Use only with extreme care.
-  void CreateBaseFileUnsafe(const FilePath& name, uint32 flags);
+  void InitializeUnsafe(const FilePath& name, uint32 flags);
 
   bool IsValid() const;
 
   // Returns true if a new file was created (or an old one truncated to zero
   // length to simulate a new file, which can happen with
   // FLAG_CREATE_ALWAYS), and false otherwise.
   bool created() const { return created_; }
 
   // Returns the OS result of opening this file.
   Error error() const { return error_; }
@@ skipping 36 matching lines @@
   // with FLAG_APPEND.
   int Write(int64 offset, const char* data, int size);
 
   // Save as above but without seek.
   int WriteAtCurrentPos(const char* data, int size);
 
   // Save as above but does not make any effort to write all data on all
   // platforms. Returns the number of bytes written, or -1 on error.
   int WriteAtCurrentPosNoBestEffort(const char* data, int size);
 
+  // Returns the current size of this file, or a negative number on failure.
+  int64 GetLength();
+
   // Truncates the file to the given length. If |length| is greater than the
   // current size of the file, the file is extended with zeros. If the file
   // doesn't exist, |false| is returned.
-  bool Truncate(int64 length);
+  bool SetLength(int64 length);
 
   // Flushes the buffers.
   bool Flush();
 
   // Updates the file times.
   bool SetTimes(Time last_access_time, Time last_modified_time);
 
   // Returns some basic information for the given file.
   bool GetInfo(Info* info);
 
@@ skipping 38 matching lines @@
 #endif
 
   Error error_;
   bool created_;
   bool async_;
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_H_