Implement FilePath::Contains()

base/file_path.h

 // Copyright (c) 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.
 
 // FilePath is a container for pathnames stored in a platform's native string
 // type, providing containers for manipulation in according with the
 // platform's conventions for pathnames.  It supports the following path
 // types:
 //
 //                   POSIX            Windows
@@ skipping 141 matching lines @@
   // it is an error to pass an absolute path.
   FilePath Append(const StringType& component) const WARN_UNUSED_RESULT;
   FilePath Append(const FilePath& component) const WARN_UNUSED_RESULT;
 
   // Returns true if this FilePath contains an absolute path.  On Windows, an
   // absolute path begins with either a drive letter specification followed by
   // a separator character, or with two separator characters.  On POSIX
   // platforms, an absolute path begins with a separator character.
   bool IsAbsolute() const;
 
+  // Returns true if this FilePath represents a parent dir of |other|. Both
+  // paths are normalized before doing the comparison, but neither |this| nor
+  // |other| are modified.
+  bool Contains(const FilePath& other) const;
+
   // Returns a copy of this FilePath that does not end with a trailing
   // separator.
   FilePath StripTrailingSeparators() const;
 
   // Older Chromium code assumes that paths are always wstrings.
   // This function converts a wstring to a FilePath, and is useful to smooth
   // porting that old code to the FilePath API.
   // It has "Hack" in its name so people feel bad about using it.
   // TODO(port): remove these functions.
   static FilePath FromWStringHack(const std::wstring& wstring);
@@ skipping 17 matching lines @@
 };
 
 // Macros for string literal initialization of FilePath::CharType[].
 #if defined(OS_POSIX)
 #define FILE_PATH_LITERAL(x) x
 #elif defined(OS_WIN)
 #define FILE_PATH_LITERAL(x) L ## x
 #endif  // OS_WIN
 
 #endif  // BASE_FILE_PATH_H_