Revert "Remove CpuMonitor and related, unused, code."

webrtc/base/cpumonitor.h

Index: webrtc/base/cpumonitor.h
diff --git a/webrtc/base/cpumonitor.h b/webrtc/base/cpumonitor.h
new file mode 100644
index 0000000000000000000000000000000000000000..e82ae695167c84d3554bda69565729cfa29fb883
--- /dev/null
+++ b/webrtc/base/cpumonitor.h
@@ -0,0 +1,123 @@
+/*
+ *  Copyright 2010 The WebRTC 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 in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_BASE_CPUMONITOR_H_
+#define WEBRTC_BASE_CPUMONITOR_H_
+
+#include "webrtc/base/basictypes.h"
+#include "webrtc/base/messagehandler.h"
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/base/sigslot.h"
+#if defined(WEBRTC_LINUX)
+#include "webrtc/base/stream.h"
+#endif // defined(WEBRTC_LINUX)
+
+namespace rtc {
+class Thread;
+class SystemInfo;
+
+struct CpuStats {
+  CpuStats()
+      : prev_total_times_(0),
+        prev_cpu_times_(0),
+        prev_load_(0.f),
+        prev_load_time_(0u) {
+  }
+
+  uint64 prev_total_times_;
+  uint64 prev_cpu_times_;
+  float prev_load_;  // Previous load value.
+  uint32 prev_load_time_;  // Time previous load value was taken.
+};
+
+// CpuSampler samples the process and system load.
+class CpuSampler {
+ public:
+  CpuSampler();
+  ~CpuSampler();
+
+  // Initialize CpuSampler.  Returns true if successful.
+  bool Init();
+
+  // Set minimum interval in ms between computing new load values.
+  // Default 950 ms.  Set to 0 to disable interval.
+  void set_load_interval(int min_load_interval);
+
+  // Return CPU load of current process as a float from 0 to 1.
+  float GetProcessLoad();
+
+  // Return CPU load of current process as a float from 0 to 1.
+  float GetSystemLoad();
+
+  // Return number of cpus. Includes hyperthreads.
+  int GetMaxCpus() const;
+
+  // Return current number of cpus available to this process.
+  int GetCurrentCpus();
+
+  // For testing. Allows forcing of fallback to using NTDLL functions.
+  void set_force_fallback(bool fallback) {
+#if defined(WEBRTC_WIN)
+    force_fallback_ = fallback;
+#endif
+  }
+
+ private:
+  float UpdateCpuLoad(uint64 current_total_times,
+                      uint64 current_cpu_times,
+                      uint64 *prev_total_times,
+                      uint64 *prev_cpu_times);
+  CpuStats process_;
+  CpuStats system_;
+  int cpus_;
+  int min_load_interval_;  // Minimum time between computing new load.
+  scoped_ptr<SystemInfo> sysinfo_;
+#if defined(WEBRTC_WIN)
+  void* get_system_times_;
+  void* nt_query_system_information_;
+  bool force_fallback_;
+#endif
+#if defined(WEBRTC_LINUX)
+  // File for reading /proc/stat
+  scoped_ptr<FileStream> sfile_;
+#endif // defined(WEBRTC_LINUX)
+};
+
+// CpuMonitor samples and signals the CPU load periodically.
+class CpuMonitor
+    : public rtc::MessageHandler, public sigslot::has_slots<> {
+ public:
+  explicit CpuMonitor(Thread* thread);
+  ~CpuMonitor() override;
+  void set_thread(Thread* thread);
+
+  bool Start(int period_ms);
+  void Stop();
+  // Signal parameters are current cpus, max cpus, process load and system load.
+  sigslot::signal4<int, int, float, float> SignalUpdate;
+
+ protected:
+  // Override virtual method of parent MessageHandler.
+  void OnMessage(rtc::Message* msg) override;
+  // Clear the monitor thread and stop sending it messages if the thread goes
+  // away before our lifetime.
+  void OnMessageQueueDestroyed() { monitor_thread_ = NULL; }
+
+ private:
+  Thread* monitor_thread_;
+  CpuSampler sampler_;
+  int period_ms_;
+
+  DISALLOW_COPY_AND_ASSIGN(CpuMonitor);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_CPUMONITOR_H_