diff --git a/update_engine.gyp b/update_engine.gyp
index 7a1ad95..41ee1e8 100644
--- a/update_engine.gyp
+++ b/update_engine.gyp
@@ -187,6 +187,7 @@
         'payload_consumer/bzip_extent_writer.cc',
         'payload_consumer/delta_performer.cc',
         'payload_consumer/download_action.cc',
+        'payload_consumer/extent_reader.cc',
         'payload_consumer/extent_writer.cc',
         'payload_consumer/file_descriptor.cc',
         'payload_consumer/file_descriptor_utils.cc',
@@ -532,6 +533,7 @@
             'payload_consumer/delta_performer_integration_test.cc',
             'payload_consumer/delta_performer_unittest.cc',
             'payload_consumer/download_action_unittest.cc',
+            'payload_consumer/extent_reader_unittest.cc',
             'payload_consumer/extent_writer_unittest.cc',
             'payload_consumer/fake_file_descriptor.cc',
             'payload_consumer/file_descriptor_utils_unittest.cc',