Add external extensions json source in proper mac location.

base/file_util.h

Index: base/file_util.h
diff --git a/base/file_util.h b/base/file_util.h
index cd7fa9fafcbe68865e578b3c173adb84419e34e7..f8e11adf7053e72413eb5e2e6cf16c83303c13c3 100644
--- a/base/file_util.h
+++ b/base/file_util.h
@@ -659,6 +659,22 @@ enum FileSystemType {
 BASE_EXPORT bool GetFileSystemType(const FilePath& path, FileSystemType* type);
 #endif
 
+#if defined(OS_POSIX)
+// Test that a path is owned by a specific user, and not writable
+// by all users.  This is useful for checking that a config file
+// is administrator-controlled.  All components of |path| after |base|
+// are checked.  Note that |base| is not checked, and |base| must be a
+// parent of |path|.
+BASE_EXPORT bool IsPathControlledByUser(const FilePath& base,
+                                        const FilePath& path,
+                                        uid_t owner_uid);
+
+// Is |path| writable only by a user with administrator privileges?
+// Check this by testing that |path|, and every parent directory,
+// are owned by root and not writable by all users.
+BASE_EXPORT bool IsPathControlledByAdmin(const FilePath& path);
+#endif  // defined(OS_POSIX)
+
 }  // namespace file_util
 
 // Deprecated functions have been moved to this separate header file,