chromeos: Add CPU temperature reader

chromeos/system/cpu_temp_reader.h

Index: chromeos/system/cpu_temp_reader.h
diff --git a/chromeos/system/cpu_temp_reader.h b/chromeos/system/cpu_temp_reader.h
new file mode 100644
index 0000000000000000000000000000000000000000..73110683c21b6d071ad3051d0072ce403fda532f
--- /dev/null
+++ b/chromeos/system/cpu_temp_reader.h
@@ -0,0 +1,30 @@
+// Copyright 2017 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 CHROMEOS_SYSTEM_CPU_TEMP_READER_H_

[Daniel Erat, 2017/04/14 18:53:32]

nit: just rename this to cpu_temperature.h if you don't plan to actually
introduce a class named CPUTemperatureReader?

[Simon Que, 2017/04/17 16:41:07]

Introducing a class.

+#define CHROMEOS_SYSTEM_CPU_TEMP_READER_H_
+
+#include <string>
+#include <vector>
+
+namespace chromeos {
+namespace system {
+
+// Contains info from a CPU temperature sensor.
+struct CPUTemperatureInfo {
+  // The temperature read by a CPU temperature sensor in degrees Celsius.
+  double temp_celsius;
+  // The name of the CPU temperature zone monitored by this sensor.
+  std::string label;

[Daniel Erat, 2017/04/14 18:53:32]

how's this going to be used? an opaque string label like this seems hard to
interpret.

[Simon Que, 2017/04/17 16:41:07]

Done.

+};
+
+// Read temperature from each thermal sensor of the CPU. Returns a vector
+// containing a reading from each sensor.
+std::vector<CPUTemperatureInfo> GetCPUTemperatures();

[stevenjb, 2017/04/14 15:44:04]

This function does file operations and there is no indication that it must be
called from a slow task runner.

It is hard to review this without the context of how it is going to be used. I
suspect that you will want this to take a callback instead of returning the
result immediately so that the function can handle that implementation detail.

[Simon Que, 2017/04/17 16:41:07]

I will leave it up to the caller to implement it with a task runner and
callback.

e.g.
https://cs.chromium.org/chromium/src/chrome/browser/chromeos/policy/device_st...

+
+}  // namespace system
+}  // namespace chromeos
+
+#endif  // CHROMEOS_SYSTEM_CPU_TEMP_READER_H_
+