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

src/v8.cc

Index: src/v8.cc
diff --git a/src/v8.cc b/src/v8.cc
index 31b48780e4f0d059f0ec218015e156600a6c71e4..7a792d66158eb95532474f11d3411ab4597d3cd1 100644
--- a/src/v8.cc
+++ b/src/v8.cc
@@ -49,7 +49,6 @@ void V8::TearDown() {
   ExternalReference::TearDownMathExpData();
   RegisteredExtension::UnregisterAll();
   Isolate::GlobalTearDown();
-  Sampler::TearDown();
   FlagList::ResetAllFlags();  // Frees memory held by string arguments.
 }
 
@@ -77,7 +76,6 @@ void V8::InitializeOncePerProcessImpl() {
 
   Isolate::InitializeOncePerProcess();
 
-  Sampler::SetUp();
   CpuFeatures::Probe(false);
   ElementsAccessor::InitializeOncePerProcess();
   LOperand::SetUpCaches();