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

src/v8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/assembler.h"
 #include "src/base/once.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
@@ skipping 31 matching lines @@
 }
 
 
 void V8::TearDown() {
   Bootstrapper::TearDownExtensions();
   ElementsAccessor::TearDown();
   LOperand::TearDownCaches();
   ExternalReference::TearDownMathExpData();
   RegisteredExtension::UnregisterAll();
   Isolate::GlobalTearDown();
-  Sampler::TearDown();
   FlagList::ResetAllFlags();  // Frees memory held by string arguments.
 }
 
 
 void V8::InitializeOncePerProcessImpl() {
   FlagList::EnforceFlagImplications();
 
   if (FLAG_predictable && FLAG_random_seed == 0) {
     // Avoid random seeds in predictable mode.
     FLAG_random_seed = 12347;
   }
 
   if (FLAG_stress_compaction) {
     FLAG_force_marking_deque_overflows = true;
     FLAG_gc_global = true;
     FLAG_max_semi_space_size = 1;
   }
 
   if (FLAG_turbo && strcmp(FLAG_turbo_filter, "~~") == 0) {
     const char* filter_flag = "--turbo-filter=*";
     FlagList::SetFlagsFromString(filter_flag, StrLength(filter_flag));
   }
 
   base::OS::Initialize(FLAG_random_seed, FLAG_hard_abort, FLAG_gc_fake_mmap);
 
   Isolate::InitializeOncePerProcess();
 
-  Sampler::SetUp();
   CpuFeatures::Probe(false);
   ElementsAccessor::InitializeOncePerProcess();
   LOperand::SetUpCaches();
   SetUpJSCallerSavedCodeData();
   ExternalReference::SetUp();
   Bootstrapper::InitializeOncePerProcess();
 }
 
 
 void V8::InitializeOncePerProcess() {
@@ skipping 34 matching lines @@
 
 void V8::SetSnapshotBlob(StartupData* snapshot_blob) {
 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
   base::CallOnce(&init_snapshot_once, &SetSnapshotFromFile, snapshot_blob);
 #else
   CHECK(false);
 #endif
 }
 }  // namespace internal
 }  // namespace v8