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

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index d8b0e9842da6cad402501aa5acfbfcc2bdf6620e..6f140e681977028532ccf8b650554ab4ff5731d3 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -9,6 +9,7 @@
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
+#include "include/v8-sampler.h"
 #include "src/ast/ast.h"
 #include "src/ast/scopeinfo.h"
 #include "src/base/platform/platform.h"
@@ -1922,7 +1923,8 @@ void Isolate::Deinit() {
   }
 
   // We must stop the logger before we tear down other components.
-  Sampler* sampler = logger_->sampler();
+  // Sampler* sampler = logger_->sampler();
+  V8Sampler* sampler = logger_->sampler();
   if (sampler && sampler->IsActive()) sampler->Stop();
 
   delete deoptimizer_data_;