[Chromoting] Retrieve process resource usage (ProcessStats) and its tests

remoting/host/process_stats_util.h

+// 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 REMOTING_HOST_PROCESS_STATS_UTIL_H_
+#define REMOTING_HOST_PROCESS_STATS_UTIL_H_
+
+#include <vector>
+
+#include "remoting/proto/process_stats.pb.h"
+
+namespace remoting {
+namespace host {

[Sergey Ulanov, 2017/04/06 05:55:50]

We have host namespace in other places. All other host-related classes are in
remoting namespace. We could add it, but I don't think it makes sense to put
just the new code you are adding in this CL. Will you move rest of host code
there?

[Hzj_jie, 2017/04/06 19:41:05]

I have not noticed it :(
I will remove the host namespace.

+
+// Whether the |usage| is empty, i.e. all fields hold initial values.
+bool IsEmptyProcessResourceUsage(const protocol::ProcessResourceUsage& usage);
+
+// Merges several ProcessResourceUsage instances into one
+// AggregatedProcessResourceUsage.
+protocol::AggregatedProcessResourceUsage AggregateProcessResourceUsage(
+    const std::vector<protocol::ProcessResourceUsage>& usages);
+
+}  // namespace host
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_PROCESS_STATS_UTIL_H_