Roll Chrome into Mojo.

base/debug/trace_event_system_stats_monitor.h

-// Copyright 2013 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_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_
-#define BASE_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_
-
-#include "base/base_export.h"
-#include "base/debug/trace_event_impl.h"
-#include "base/gtest_prod_util.h"
-#include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
-#include "base/process/process_metrics.h"
-#include "base/timer/timer.h"
-
-namespace base {
-
-class SingleThreadTaskRunner;
-
-namespace debug {
-
-// Watches for chrome://tracing to be enabled or disabled. When tracing is
-// enabled, also enables system events profiling. This class is the preferred
-// way to turn system tracing on and off.
-class BASE_EXPORT TraceEventSystemStatsMonitor
-    : public TraceLog::EnabledStateObserver {
- public:
-  // Length of time interval between stat profiles.
-  static const int kSamplingIntervalMilliseconds = 2000;
-
-  // |task_runner| must be the primary thread for the client
-  // process, e.g. the UI thread in a browser.
-  explicit TraceEventSystemStatsMonitor(
-      scoped_refptr<SingleThreadTaskRunner> task_runner);
-
-  virtual ~TraceEventSystemStatsMonitor();
-
-  // base::debug::TraceLog::EnabledStateChangedObserver overrides:
-  void OnTraceLogEnabled() override;
-  void OnTraceLogDisabled() override;
-
-  // Retrieves system profiling at the current time.
-  void DumpSystemStats();
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(TraceSystemStatsMonitorTest,
-                           TraceEventSystemStatsMonitor);
-
-  bool IsTimerRunningForTest() const;
-
-  void StartProfiling();
-
-  void StopProfiling();
-
-  // Ensures the observer starts and stops tracing on the primary thread.
-  scoped_refptr<SingleThreadTaskRunner> task_runner_;
-
-  // Timer to schedule system profile dumps.
-  RepeatingTimer<TraceEventSystemStatsMonitor> dump_timer_;
-
-  WeakPtrFactory<TraceEventSystemStatsMonitor> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(TraceEventSystemStatsMonitor);
-};
-
-// Converts system memory profiling stats in |input| to
-// trace event compatible JSON and appends to |output|. Visible for testing.
-BASE_EXPORT void AppendSystemProfileAsTraceFormat(const SystemMetrics&
-                                                  system_stats,
-                                                  std::string* output);
-
-}  // namespace debug
-}  // namespace base
-
-#endif  // BASE_DEBUG_TRACE_EVENT_SYSTEM_STATS_MONITOR_H_