[profiler] Introduce Tracing CPU profiler V8 API.

src/profiler/tracing-cpu-profiler.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_PROFILER_TRACING_CPU_PROFILER_H
+#define V8_PROFILER_TRACING_CPU_PROFILER_H
+
+#include "include/v8-profiler.h"
+#include "src/base/macros.h"
+
+namespace v8 {
+namespace internal {
+
+class TracingCpuProfilerImpl final : public TracingCpuProfiler {
+ public:
+  explicit TracingCpuProfilerImpl(Isolate*);
+  ~TracingCpuProfilerImpl();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TracingCpuProfilerImpl);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_PROFILER_TRACING_CPU_PROFILER_H