Creating a framework for suppressing pollution of the profiler data

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..c698760e5bd7b9940fb3fa530bb7c38a9a8f85bd 100644
--- a/base/threading/worker_pool_win.cc
+++ b/base/threading/worker_pool_win.cc
@@ -25,17 +25,20 @@ DWORD CALLBACK WorkItemCallback(void* param) {
                "src_file", pending_task->posted_from.file_name(),
                "src_func", pending_task->posted_from.function_name());
 
-  tracked_objects::TrackedTime start_time =
-      tracked_objects::ThreadData::NowForStartOfRun(pending_task->birth_tally);
+  tracked_objects::TaskStopwatch stopwatch;

[jar (doing other things), 2014/08/26 04:09:09]

nit/Question: Is there ever a case where we don't construct a TaskStopwatch, and
then immediately call its Start() method?  

I was wondering why the constructor doesn't take the argument to the Start()
method, and be done with it??

[vadimt, 2014/08/26 19:15:04]

No, but since there is method Stop, I thought it would be strange to have:
tracked_objects::TaskStopwatch stopwatch(time);
stopwatch.Stop()

You might argue that the stopwatch could be stopped inside
TallyRunOnWorkerThreadIfTracking(), but this would make code harder to
understand. Basically, if you start the stopwatch in constructor, you should
stop it in destructor, which is not the case here.
Note that we have asserts that the stopwatch passed to
TallyRunOnWorkerThreadIfTracking() was started and stopped.

+  stopwatch.Start(
+    tracked_objects::ThreadData::NowForStartOfRun(pending_task->birth_tally));
 
   g_worker_pool_running_on_this_thread.Get().Set(true);
   pending_task->task.Run();
   g_worker_pool_running_on_this_thread.Get().Set(false);
 
+  stopwatch.Stop(tracked_objects::ThreadData::NowForEndOfRun());
+
   tracked_objects::ThreadData::TallyRunOnWorkerThreadIfTracking(
       pending_task->birth_tally,
-      tracked_objects::TrackedTime(pending_task->time_posted), start_time,
-      tracked_objects::ThreadData::NowForEndOfRun());
+      tracked_objects::TrackedTime(pending_task->time_posted),
+      stopwatch);
 
   delete pending_task;
   return 0;