gn: fix bootstrap.py after https://codereview.chromium.org/2846893003

BUG=none

Review-Url: https://codereview.chromium.org/2860753004
Cr-Original-Commit-Position: refs/heads/master@{#469332}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 643d6bc90fead3ccefa9309d265dd048e51c263f
diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index 9b5bbcc..5ba591a 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -629,6 +629,7 @@
         'tool': 'cxx',
     }
     static_libraries['base']['sources'].extend([
+        'base/memory/shared_memory_handle_posix.cc',
         'base/memory/shared_memory_posix.cc',
         'base/memory/shared_memory_tracker.cc',
         'base/nix/xdg_util.cc',