tracing: remove sampling state profiler

base/trace_event/trace_sampling_thread.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_TRACE_EVENT_TRACE_SAMPLING_THREAD_H_
-#define BASE_TRACE_EVENT_TRACE_SAMPLING_THREAD_H_
-
-#include "base/synchronization/cancellation_flag.h"
-#include "base/synchronization/waitable_event.h"
-#include "base/trace_event/trace_event.h"
-
-namespace base {
-namespace trace_event {
-
-class TraceBucketData;
-typedef base::Callback<void(TraceBucketData*)> TraceSampleCallback;
-
-// This object must be created on the IO thread.
-class TraceSamplingThread : public PlatformThread::Delegate {
- public:
-  TraceSamplingThread();
-  ~TraceSamplingThread() override;
-
-  // Implementation of PlatformThread::Delegate:
-  void ThreadMain() override;
-
-  static void DefaultSamplingCallback(TraceBucketData* bucket_data);
-
-  void Stop();
-  void WaitSamplingEventForTesting();
-
- private:
-  friend class TraceLog;
-
-  void GetSamples();
-  // Not thread-safe. Once the ThreadMain has been called, this can no longer
-  // be called.
-  void RegisterSampleBucket(TRACE_EVENT_API_ATOMIC_WORD* bucket,
-                            const char* const name,
-                            TraceSampleCallback callback);
-  // Splits a combined "category\0name" into the two component parts.
-  static void ExtractCategoryAndName(const char* combined,
-                                     const char** category,
-                                     const char** name);
-  std::vector<TraceBucketData> sample_buckets_;
-  bool thread_running_;
-  CancellationFlag cancellation_flag_;
-  WaitableEvent waitable_event_for_testing_;
-};
-
-}  // namespace trace_event
-}  // namespace base
-
-#endif  // BASE_TRACE_EVENT_TRACE_SAMPLING_THREAD_H_