diff --git a/update_engine.gyp b/update_engine.gyp
index 3df48f1..b1ee122 100644
--- a/update_engine.gyp
+++ b/update_engine.gyp
@@ -280,6 +280,7 @@
         'payload_generator/cycle_breaker.cc',
         'payload_generator/delta_diff_generator.cc',
         'payload_generator/extent_mapper.cc',
+        'payload_generator/extent_utils.cc',
         'payload_generator/filesystem_iterator.cc',
         'payload_generator/full_update_generator.cc',
         'payload_generator/graph_types.cc',
@@ -373,6 +374,7 @@
             'payload_generator/cycle_breaker_unittest.cc',
             'payload_generator/delta_diff_generator_unittest.cc',
             'payload_generator/extent_mapper_unittest.cc',
+            'payload_generator/extent_utils_unittest.cc',
             'payload_generator/filesystem_iterator_unittest.cc',
             'payload_generator/full_update_generator_unittest.cc',
             'payload_generator/graph_utils_unittest.cc',