Improve test-cpu-profiler.cc tests stability

src/sampler.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 640 matching lines @@
 void Sampler::TearDown() {
   SamplerThread::TearDown();
 }
 
 
 Sampler::Sampler(Isolate* isolate, int interval)
     : isolate_(isolate),
       interval_(interval),
       profiling_(false),
       active_(false),
-      samples_taken_(0) {
+      is_counting_samples_(false),
+      js_and_external_sample_count_(0) {
   data_ = new PlatformData;
 }
 
 
 Sampler::~Sampler() {
   ASSERT(!IsActive());
   delete data_;
 }
 
 
 void Sampler::Start() {
   ASSERT(!IsActive());
   SetActive(true);
   SamplerThread::AddActiveSampler(this);
 }
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SamplerThread::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 void Sampler::SampleStack(const RegisterState& state) {
   TickSample* sample = isolate_->cpu_profiler()->TickSampleEvent();
   TickSample sample_obj;
   if (sample == NULL) sample = &sample_obj;
   sample->Init(isolate_, state);
-  if (++samples_taken_ < 0) samples_taken_ = 0;
+  if (is_counting_samples_) {
+    if (sample->state == JS || sample->state == EXTERNAL) {
+      ++js_and_external_sample_count_;
+    }
+  }
   Tick(sample);
 }
 
 } }  // namespace v8::internal