CC: Add 'cc-benchmark' traces for minimal tracing in benchmarks.

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 8dd323b5b1ffb96f9e7f0c9a8f689394eccb1172..c27010fb12f5789e5582c43d86d0958b817d109d 100644
--- a/base/threading/worker_pool_win.cc
+++ b/base/threading/worker_pool_win.cc
@@ -21,7 +21,7 @@ base::LazyInstance<ThreadLocalBoolean>::Leaky
 
 DWORD CALLBACK WorkItemCallback(void* param) {
   PendingTask* pending_task = static_cast<PendingTask*>(param);
-  TRACE_EVENT2("toplevel", "WorkItemCallback::Run",
+  TRACE_EVENT2("task", "WorkItemCallback::Run",
                "src_file", pending_task->posted_from.file_name(),
                "src_func", pending_task->posted_from.function_name());