Use boolean instead of Atomic32 for is_profiling_ flag

src/cpu-profiler.cc

Index: src/cpu-profiler.cc
diff --git a/src/cpu-profiler.cc b/src/cpu-profiler.cc
index 3cbac77858d5560feb3cab420f08c9e461f2422e..64a26c8c1956a7b19c50cf384db19ca82b7bb35e 100644
--- a/src/cpu-profiler.cc
+++ b/src/cpu-profiler.cc
@@ -491,7 +491,7 @@ void CpuProfiler::StartProcessorIfNotStarted() {
     isolate->logger()->logging_nesting_ = 0;
     generator_ = new ProfileGenerator(profiles_);
     processor_ = new ProfilerEventsProcessor(generator_);
-    NoBarrier_Store(&is_profiling_, true);
+    is_profiling_ = true;
     processor_->Start();
     // Enumerate stuff we already have in the heap.
     if (isolate->heap()->HasBeenSetUp()) {
@@ -552,7 +552,7 @@ void CpuProfiler::StopProcessor() {
     sampler->Stop();
     need_to_stop_sampler_ = false;
   }
-  NoBarrier_Store(&is_profiling_, false);
+  is_profiling_ = false;
   processor_->Stop();
   processor_->Join();
   delete processor_;