[WIP]Create a V8 sampler library and tracing controller.

test/cctest/test-cpu-profiler.cc

Index: test/cctest/test-cpu-profiler.cc
diff --git a/test/cctest/test-cpu-profiler.cc b/test/cctest/test-cpu-profiler.cc
index 361c879af39935f40b845e57d6cc3d3ab0948f18..847ba381d93d5829117cb0a45aa557c58f7e8a34 100644
--- a/test/cctest/test-cpu-profiler.cc
+++ b/test/cctest/test-cpu-profiler.cc
@@ -30,6 +30,7 @@
 #include "src/v8.h"
 
 #include "include/v8-profiler.h"
+#include "include/v8-sampler.h"
 #include "src/base/platform/platform.h"
 #include "src/base/smart-pointers.h"
 #include "src/deoptimizer.h"
@@ -429,7 +430,7 @@ static v8::CpuProfile* RunProfiler(v8::Local<v8::Context> env,
   cpu_profiler->SetSamplingInterval(100);
   cpu_profiler->StartProfiling(profile_name, collect_samples);
 
-  i::Sampler* sampler =
+  v8::V8Sampler* sampler =
       reinterpret_cast<i::Isolate*>(env->GetIsolate())->logger()->sampler();
   sampler->StartCountingSamples();
   do {