Revert of Temporary commit to evaluate perf impact of prototype CPU profiler

base/profiler/cpu_profiler.h

-// Copyright 2015 The Chromium 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 BASE_PROFILER_CPU_PROFILER_H_
-#define BASE_PROFILER_CPU_PROFILER_H_
-
-#include <map>
-
-#include "base/base_export.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/strings/string16.h"
-#include "base/synchronization/waitable_event.h"
-#include "base/timer/timer.h"
-
-namespace base {
-
-#if defined(OS_WIN)
-struct StackTraceEntry {
-  DWORD64 rsp;
-  DWORD64 rip;
-  HMODULE module;
-};
-#endif
-
-// CpuProfiler is a prototype of a technique that periodically stops the main
-// thread to samples its stack. It does not do anything useful with the
-// collected information yet; this implementation is for the purposes of
-// determining perf impact of the profiler itself.
-//
-// Currently, this is intended to sample the main thread. It should be allocated
-// on that thread, then Initialize should be called to start the sampling, and
-// Stop called to stop the sampling.
-class BASE_EXPORT CpuProfiler {
- public:
-  CpuProfiler();
-  ~CpuProfiler();
-
-  void Initialize(const std::map<std::string, std::string>* params);
-  void Stop();
-
-  std::string GetStringParam(const std::string& key) const;
-  int GetIntParam(const std::string& key) const;
-  int64 GetInt64Param(const std::string& key) const;
-
- private:
-  class SamplingThread;
-  struct SamplingThreadDeleter {
-    void operator() (SamplingThread* thread) const;
-  };
-
-  static bool IsPlatformSupported();
-
-  void SetParams(const std::map<std::string, std::string>& params);
-
-  void OnTimer();
-
-#if defined(OS_WIN)
-  void ProcessStack(StackTraceEntry* stack, int stack_depth);
-
-  HANDLE main_thread_;
-  int main_thread_stack_depth_;
-  StackTraceEntry main_thread_stack_[64];
-
-  std::map<HMODULE, base::string16> modules_;
-#endif
-
-  std::map<std::string, std::string> params_;
-
-  scoped_ptr<SamplingThread, SamplingThreadDeleter> sampling_thread_;
-  PlatformThreadHandle sampling_thread_handle_;
-
-  DISALLOW_COPY_AND_ASSIGN(CpuProfiler);
-};
-
-}  // namespace base
-
-#endif   // BASE_PROFILER_CPU_PROFILER_H_