diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index 8252799..5b71d94 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -524,6 +524,7 @@
       'base/trace_event/memory_dump_session_state.cc',
       'base/trace_event/memory_infra_background_whitelist.cc',
       'base/trace_event/memory_peak_detector.cc',
+      'base/trace_event/memory_tracing_observer.cc',
       'base/trace_event/process_memory_dump.cc',
       'base/trace_event/process_memory_maps.cc',
       'base/trace_event/process_memory_totals.cc',