diff --git a/update_engine.gyp b/update_engine.gyp
index 38d6ba1..e6ff776 100644
--- a/update_engine.gyp
+++ b/update_engine.gyp
@@ -398,6 +398,7 @@
         'payload_generator/graph_types.cc',
         'payload_generator/graph_utils.cc',
         'payload_generator/inplace_generator.cc',
+        'payload_generator/mapfile_filesystem.cc',
         'payload_generator/payload_file.cc',
         'payload_generator/payload_generation_config.cc',
         'payload_generator/payload_signer.cc',
@@ -542,6 +543,7 @@
             'payload_generator/full_update_generator_unittest.cc',
             'payload_generator/graph_utils_unittest.cc',
             'payload_generator/inplace_generator_unittest.cc',
+            'payload_generator/mapfile_filesystem_unittest.cc',
             'payload_generator/payload_file_unittest.cc',
             'payload_generator/payload_generation_config_unittest.cc',
             'payload_generator/payload_signer_unittest.cc',