Match whole path components in DevicePathToDriveLetterPath(). Add tests.

base/file_util.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// 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.
 
 // This file contains utility functions for dealing with the local
 // filesystem.
 
 #ifndef BASE_FILE_UTIL_H_
 #define BASE_FILE_UTIL_H_
 #pragma once
 
@@ skipping 305 matching lines @@
 
 // Sets |real_path| to |path| with symbolic links and junctions expanded.
 // On windows, make sure the path starts with a lettered drive.
 // |path| must reference a file.  Function will fail if |path| points to
 // a directory or to a nonexistent path.  On windows, this function will
 // fail if |path| is a junction or symlink that points to an empty file,
 // or if |real_path| would be longer than MAX_PATH characters.
 BASE_EXPORT bool NormalizeFilePath(const FilePath& path, FilePath* real_path);
 
 #if defined(OS_WIN)
-// Given an existing file in |path|, it returns in |real_path| the path
-// in the native NT format, of the form "\Device\HarddiskVolumeXX\..".
-// Returns false it it fails. Empty files cannot be resolved with this
-// function.
+
+// Given a path in NT native form ("\Device\HarddiskVolumeXX\..."),
+// return in |drive_letter_path| the equivalent path that starts with
+// a drive letter ("C:\...").  Return false if no such path exists.
+BASE_EXPORT bool DevicePathToDriveLetterPath(const FilePath& device_path,
+                                             FilePath* drive_letter_path);
+
+// Given an existing file in |path|, set |real_path| to the path
+// in native NT format, of the form "\Device\HarddiskVolumeXX\..".
+// Returns false if the path can not be found. Empty files cannot
+// be resolved with this function.
 BASE_EXPORT bool NormalizeToNativeFilePath(const FilePath& path,
                                            FilePath* nt_path);
 #endif
 
 // This function will return if the given file is a symlink or not.
 BASE_EXPORT bool IsLink(const FilePath& file_path);
 
 // Returns information about the given file path.
 BASE_EXPORT bool GetFileInfo(const FilePath& file_path,
                              base::PlatformFileInfo* info);
@@ skipping 290 matching lines @@
 BASE_EXPORT bool GetFileSystemType(const FilePath& path, FileSystemType* type);
 #endif
 
 }  // namespace file_util
 
 // Deprecated functions have been moved to this separate header file,
 // which must be included last after all the above definitions.
 #include "base/file_util_deprecated.h"
 
 #endif  // BASE_FILE_UTIL_H_