Creating a framework for suppressing pollution of the profiler data

base/message_loop/message_loop.cc

Index: base/message_loop/message_loop.cc
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index dd1a393ab08633514df9d6d021a1be7ff4dbd23f..f39b05088e5a1cfb45684eaa63b9726cd8fe1d7a 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -415,13 +415,14 @@ bool MessageLoop::ProcessNextDelayedNonNestableTask() {
 }
 
 void MessageLoop::RunTask(const PendingTask& pending_task) {
-  tracked_objects::TrackedTime start_time =
-      tracked_objects::ThreadData::NowForStartOfRun(pending_task.birth_tally);
+  tracked_objects::ThreadData::PrepareForStartOfRun(pending_task.birth_tally);
+  tracked_objects::TaskStopwatch stopwatch;
 
   TRACE_EVENT_FLOW_END1(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"),
       "MessageLoop::PostTask", TRACE_ID_MANGLE(GetTaskTraceID(pending_task)),
       "queue_duration",
-      (start_time - pending_task.EffectiveTimePosted()).InMilliseconds());
+      (stopwatch.StartTime() - pending_task.EffectiveTimePosted()).
+          InMilliseconds());
   // When tracing memory for posted tasks it's more valuable to attribute the
   // memory allocations to the source function than generically to "RunTask".
   TRACE_EVENT_WITH_MEMORY_TAG2(
@@ -451,8 +452,9 @@ void MessageLoop::RunTask(const PendingTask& pending_task) {
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
                     DidProcessTask(pending_task));
 
-  tracked_objects::ThreadData::TallyRunOnNamedThreadIfTracking(pending_task,
-      start_time, tracked_objects::ThreadData::NowForEndOfRun());
+  stopwatch.Stop();
+  tracked_objects::ThreadData::TallyRunOnNamedThreadIfTracking(
+      pending_task, stopwatch);
 
   nestable_tasks_allowed_ = true;
 }