Perform CPU sampling by CPU sampling thread only iff processing thread is not running.

src/platform-freebsd.cc

Index: src/platform-freebsd.cc
diff --git a/src/platform-freebsd.cc b/src/platform-freebsd.cc
index 526fecf326ee9c7928c9360be84896e3168c0aa0..3ec02b780c047ca157163384cb056c37c39d5c70 100644
--- a/src/platform-freebsd.cc
+++ b/src/platform-freebsd.cc
@@ -684,8 +684,9 @@ 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::StartTickSampleEvent(isolate);
-  if (sample == NULL) return;
+  if (sample == NULL) sample = &sample_obj;
 
   // Extracting the sample from the context is extremely machine dependent.
   ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
@@ -909,4 +910,12 @@ void Sampler::Stop() {
 }
 
 
+void Sampler::StartSampling() {
+}
+
+
+void Sampler::StopSampling() {
+}
+
+
 } }  // namespace v8::internal