Replacing circular queue by single buffer in CPU Profiler.

src/platform-openbsd.cc

Index: src/platform-openbsd.cc
diff --git a/src/platform-openbsd.cc b/src/platform-openbsd.cc
index fba295ad377d05762c065ad6c95969d93489d676..5920e56e142df249074ca7bcac590356ff887f60 100644
--- a/src/platform-openbsd.cc
+++ b/src/platform-openbsd.cc
@@ -734,9 +734,8 @@ static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
   Sampler* sampler = isolate->logger()->sampler();
   if (sampler == NULL || !sampler->IsActive()) return;
 
-  TickSample sample_obj;
-  TickSample* sample = CpuProfiler::TickSampleEvent(isolate);
-  if (sample == NULL) sample = &sample_obj;
+  TickSample* sample = CpuProfiler::StartTickSampleEvent(isolate);
+  if (sample == NULL) return;
 
   // Extracting the sample from the context is extremely machine dependent.
   sample->state = isolate->current_vm_state();
@@ -765,6 +764,7 @@ static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
 #endif  // __NetBSD__
   sampler->SampleStack(sample);
   sampler->Tick(sample);
+  CpuProfiler::FinishTickSampleEvent(isolate);
 }