Fix race in CpuProfiler::StopProcessor / CpuProfiler::TickSampleEvent.

src/cpu-profiler.cc

Index: src/cpu-profiler.cc
diff --git a/src/cpu-profiler.cc b/src/cpu-profiler.cc
index 65490285e75fa87f01a337d43bcd4189059e3a40..d74c034ac53a0a68b74feef3b09e00398fa019a6 100644
--- a/src/cpu-profiler.cc
+++ b/src/cpu-profiler.cc
@@ -551,12 +551,12 @@ void CpuProfiler::StopProcessor() {
     sampler->Stop();
     need_to_stop_sampler_ = false;
   }
+  NoBarrier_Store(&is_profiling_, false);
   processor_->Stop();
   processor_->Join();
   delete processor_;
   delete generator_;
   processor_ = NULL;
-  NoBarrier_Store(&is_profiling_, false);
   generator_ = NULL;
   logger->logging_nesting_ = saved_logging_nesting_;
 }