Add base/files/file_tracing.cc to tools/gn/bootstrap/bootstrap.py.

BUG=491951

Review URL: https://codereview.chromium.org/1144003003

Cr-Original-Commit-Position: refs/heads/master@{#331315}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 58a1b336e86f925eac8054e6d73f12bc026bbe60

tools/gn/bootstrap/bootstrap.py

diff --git a/tools/gn/bootstrap/bootstrap.py b/tools/gn/bootstrap/bootstrap.py
index b417dee..373883f 100755
--- a/tools/gn/bootstrap/bootstrap.py
+++ b/tools/gn/bootstrap/bootstrap.py
@@ -156,6 +156,7 @@
       'base/files/file_enumerator.cc',
       'base/files/file_path.cc',
       'base/files/file_path_constants.cc',
+      'base/files/file_tracing.cc',
       'base/files/file_util.cc',
       'base/files/scoped_file.cc',
       'base/json/json_parser.cc',