Chrome power profiler service

content/browser/power_profiler/power_data_provider.h

+// Copyright 2014 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 CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_H_
+#define CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time/time.h"
+
+namespace content {
+
+// PowerEvent here is the total power of SoC, including CPU, GPU and others
+// on the chip, modules out of SoC such as screen is not included.
+struct PowerEvent {
+  base::TimeTicks time; // Time that power data was read.
+
+  // Power value between last event to this one, in watt.
+  // E.g, event1 {t1, v1}; event2 {t2, v2}; event3 {t3, v3}.
+  // Suppose event1 is the first event observer received, then event2, event3.
+  // Then v2 is average power from t1 to t2, v3 is the average power from t2 to
+  // t3. v1 should be ignored since event1 only means the start point of power
+  // profiling.
+  double value;

[qsr, 2014/02/10 14:02:49]

See jeremy@ message, we probably want an enum there. The question then is
whether we want to received one data point at a time, or multiple data point on
a single event.

[Pan, 2014/02/11 02:03:23]

done.
IMHO, we should provide per data here, and allow its client
to filter/buffer the events, any idea?

Pan

+};
+
+// a class used to GET power usage.
+class PowerDataProvider {
+ public:
+  PowerDataProvider() {}
+  virtual ~PowerDataProvider() {}
+
+  // Return true when success, it fills a single PowerEvent, which should be
+  // allocated by its caller.
+  virtual bool GetData(PowerEvent*) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(PowerDataProvider);
+};
+
+class PowerDataProviderFactory {
+ public:
+  // Create a provider, and transfer the ownership to PowerProfilerService.
+  static scoped_ptr<PowerDataProvider> Create();
+
+ private:
+  PowerDataProviderFactory() {}
+  DISALLOW_COPY_AND_ASSIGN(PowerDataProviderFactory);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_POWER_PROFILER_POWER_DATA_PROVIDER_H_