Cleanup: removing unused descendants information from tracked objects

base/threading/worker_pool_win.cc

Index: base/threading/worker_pool_win.cc
diff --git a/base/threading/worker_pool_win.cc b/base/threading/worker_pool_win.cc
index 54694396a328f0156bd4396fe4cf695cb8a140ae..1b0ade5e244c9495570a126b00c080c53943a6ae 100644
--- a/base/threading/worker_pool_win.cc
+++ b/base/threading/worker_pool_win.cc
@@ -25,8 +25,6 @@ DWORD CALLBACK WorkItemCallback(void* param) {
                "src_file", pending_task->posted_from.file_name(),
                "src_func", pending_task->posted_from.function_name());
 
-  tracked_objects::ThreadData::PrepareForStartOfRun(pending_task->birth_tally);
-
   g_worker_pool_running_on_this_thread.Get().Set(true);
 
   tracked_objects::TaskStopwatch stopwatch;