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

src/platform-win32.cc

Index: src/platform-win32.cc
diff --git a/src/platform-win32.cc b/src/platform-win32.cc
index 65d31a94f9174c23e72ad0a26e199ef0deda29e2..7c34312650bed98cc9dd6ded96a6d45f91df4d36 100644
--- a/src/platform-win32.cc
+++ b/src/platform-win32.cc
@@ -2038,8 +2038,9 @@ class SamplerThread : public Thread {
     CONTEXT context;
     memset(&context, 0, sizeof(context));
 
-    TickSample* sample = CpuProfiler::StartTickSampleEvent(sampler->isolate());
-    if (sample == NULL) return;
+    TickSample sample_obj;
+    TickSample* sample = CpuProfiler::StartTickSampleEvent(isolate);
+    if (sample == NULL) sample = &sample_obj;
 
     static const DWORD kSuspendFailed = static_cast<DWORD>(-1);
     if (SuspendThread(profiled_thread) == kSuspendFailed) return;
@@ -2133,4 +2134,12 @@ void Sampler::Stop() {
 }
 
 
+void Sampler::StartSampling() {
+}
+
+
+void Sampler::StopSampling() {
+}
+
+
 } }  // namespace v8::internal