Add the methods to change and get a posix file permission to file_util.

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index 53eefcc4de1f2a71bb316a44bf97240dd70052dc..e374fa17ee49bda1a83a78eacee618146933cbf1 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -196,6 +196,37 @@ BASE_EXPORT bool CreateSymbolicLink(const FilePath& target,
 // Reads the given |symlink| and returns where it points to in |target|.
 // Returns false upon failure.
 BASE_EXPORT bool ReadSymbolicLink(const FilePath& symlink, FilePath* target);
+
+// Bits ans masks of the file permission.
+enum FilePermissionBits {
+  FILE_PERMISSION_MASK              = 00777,
+  FILE_PERMISSION_USER_MASK         = 00700,
+  FILE_PERMISSION_GROUP_MASK        = 00070,
+  FILE_PERMISSION_OTHERS_MASK       = 00007,

[satorux1, 2012/07/04 16:10:41]

Not sure if thees masks are needed. maybe remove?

[yoshiki, 2012/07/09 23:44:11]

These are used at file_util_unittest.cc. Keeping.

On 2012/07/04 16:10:41, satorux1 wrote:

+
+  FILE_PERMISSION_READ_BY_USER      = 00400,

[satorux1, 2012/07/04 16:10:41]

Use sys/stat.h constants?
FILE_PERMISSION_READ_BY_USER = S_IRUSR

[yoshiki, 2012/07/09 23:44:11]

Done.

+  FILE_PERMISSION_WRITE_BY_USER     = 00200,
+  FILE_PERMISSION_EXECUTE_BY_USER   = 00100,
+  FILE_PERMISSION_READ_BY_GROUP     = 00040,
+  FILE_PERMISSION_WRITE_BY_GROUP    = 00020,
+  FILE_PERMISSION_EXECUTE_BY_GROUP  = 00010,
+  FILE_PERMISSION_READ_BY_OTHERS    = 00004,
+  FILE_PERMISSION_WRITE_BY_OTHERS   = 00002,
+  FILE_PERMISSION_EXECUTE_BY_OTHERS = 00001,
+};
+
+// Reads the permission of the given |path|, storing the file permission
+// bits in |mode|. If |path| is symbolic link, |mode| is the permission of
+// a file which the symlink refers to.
+BASE_EXPORT bool GetPosixFilePermissions(const FilePath& path,
+                                         int* mode);
+// Sets the permission of the given |path|.
+BASE_EXPORT bool SetPosixFilePermissions(const FilePath& path,
+                                         int mode);
+// Changes the permission of the given |path|.
+BASE_EXPORT bool ChangePosixFilePermissions(const FilePath& path,
+                                            int mode_bits_to_set,
+                                            int mode_bits_to_clear);

[satorux1, 2012/07/04 16:10:41]

This function seems to be unnecessary as public API. Move this to the
unittest.cc file?

[yoshiki, 2012/07/09 23:44:11]

Done.

 #endif  // defined(OS_POSIX)
 
 #if defined(OS_WIN)