diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index 8f32161..e916dad 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -533,6 +533,7 @@
       'base/message_loop/message_loop_task_runner.cc',
       'base/message_loop/message_pump.cc',
       'base/message_loop/message_pump_default.cc',
+      'base/message_loop/watchable_io_message_pump_posix.cc',
       'base/metrics/bucket_ranges.cc',
       'base/metrics/dummy_histogram.cc',
       'base/metrics/field_trial.cc',