Remove ANNOTATE_BENIGN_RACE from trace_event_synthetic_delay.cc

base/trace_event/trace_event_synthetic_delay.cc

Index: base/trace_event/trace_event_synthetic_delay.cc
diff --git a/base/trace_event/trace_event_synthetic_delay.cc b/base/trace_event/trace_event_synthetic_delay.cc
index cfae7435e9ba9ff30b98ca268520bdaf8aab681b..5f0cfbb1b08c7b4c0b99481d6b153bb916fe2cd8 100644
--- a/base/trace_event/trace_event_synthetic_delay.cc
+++ b/base/trace_event/trace_event_synthetic_delay.cc
@@ -76,12 +76,6 @@ void TraceEventSyntheticDelay::SetClock(TraceEventSyntheticDelayClock* clock) {
 }
 
 void TraceEventSyntheticDelay::Begin() {
-  // Note that we check for a non-zero target duration without locking to keep
-  // things quick for the common case when delays are disabled. Since the delay
-  // calculation is done with a lock held, it will always be correct. The only
-  // downside of this is that we may fail to apply some delays when the target
-  // duration changes.
-  ANNOTATE_BENIGN_RACE(&target_duration_, "Synthetic delay duration");

[Sami, 2017/03/21 11:52:55]

There is actually a race here (SetTargetDuration writes to target_duration_ and
we read it without locking), but we just don't have enough code using synthetic
delays to trigger it. Actually I'm considering deleting the entire synthetic
delay subsystem since we haven't really made use of it recently. If you want to
remove the macros before that that's fine, but please leave a comment here
saying there is an actual race.

   if (!target_duration_.ToInternalValue())
     return;
 
@@ -95,8 +89,6 @@ void TraceEventSyntheticDelay::Begin() {
 }
 
 void TraceEventSyntheticDelay::BeginParallel(TimeTicks* out_end_time) {
-  // See note in Begin().
-  ANNOTATE_BENIGN_RACE(&target_duration_, "Synthetic delay duration");
   if (!target_duration_.ToInternalValue()) {
     *out_end_time = TimeTicks();
     return;
@@ -110,8 +102,6 @@ void TraceEventSyntheticDelay::BeginParallel(TimeTicks* out_end_time) {
 }
 
 void TraceEventSyntheticDelay::End() {
-  // See note in Begin().
-  ANNOTATE_BENIGN_RACE(&target_duration_, "Synthetic delay duration");
   if (!target_duration_.ToInternalValue())
     return;