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

include/v8-tracing-controller.h

+// Copyright 2016 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.
+
+#ifndef V8_TRACING_CONTROLLER_H_
+#define V8_TRACING_CONTROLLER_H_
+
+#include "include/v8-sampler.h"
+#include "src/base/platform/elapsed-timer.h"
+
+namespace v8 {
+
+namespace internal {
+struct TickSample;
+}
+
+class Isolate;
+class Profiler;
+class Ticker;
+class TracingLogger;
+struct JitCodeEvent;
+
+class TracingController {
+ public:
+  static void SetUp() {
+    if (!TracingController::mutex_)
+      TracingController::mutex_ = new base::Mutex();
+    V8Sampler::SetUp();
+  }
+  static void TearDown() {
+    V8Sampler::TearDown();
+    delete mutex_;
+    mutex_ = NULL;
+  }
+  static void StartTracing(Isolate* isolate);
+  static void StopTracing();
+  static void SetInterval(int interval);
+
+  Isolate* isolate() const { return isolate_; }
+  bool IsTracing() const { return is_tracing_; }
+ private:
+  static void InstallJitCodeEventHandler(Isolate* isolate, void* data);
+  static void HandleJitCodeEvent(const JitCodeEvent* event);
+  void Start();
+  void Stop();
+  TracingController(Isolate* isolate);
+  void LogSample(i::TickSample* sample, bool overflow);
+  friend class Profiler;
+  friend class Ticker;
+
+  base::ElapsedTimer timer_;
+  bool is_tracing_;
+  Isolate* isolate_;
+  Profiler* profiler_;
+  Ticker* ticker_;
+  TracingLogger* logger_;
+  static base::Mutex* mutex_;
+  static TracingController* tracing_controller_;
+};
+
+}
+
+#endif  // V8_TRACING_CONTROLLER_H_