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

remoting/base/process_stats_util.cc

+// 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.
+
+#include "remoting/base/process_stats_util.h"
+
+namespace remoting {
+
+bool IsEmptyProcessResourceUsage(const protocol::ProcessResourceUsage& usage) {
+  return !usage.has_process_name() && !usage.has_processor_usage() &&
+         !usage.has_working_set_size() && !usage.has_pagefile_size();
+}
+
+protocol::AggregatedProcessResourceUsage AggregateProcessResourceUsage(
+    const std::vector<protocol::ProcessResourceUsage>& usages) {
+  if (usages.empty()) {
+    return protocol::AggregatedProcessResourceUsage();
+  }
+
+  if (usages.size() == 1) {
+    const protocol::ProcessResourceUsage& usage = usages[0];
+    protocol::AggregatedProcessResourceUsage aggregated;
+    aggregated.set_name(usage.process_name());
+    aggregated.set_processor_usage(usage.processor_usage());
+    aggregated.set_working_set_size(usage.working_set_size());
+    aggregated.set_pagefile_size(usage.pagefile_size());
+    return aggregated;
+  }
+
+  protocol::AggregatedProcessResourceUsage aggregated;
+  *aggregated.mutable_name() = "aggregate { ";
+  for (const auto& usage : usages) {
+    aggregated.mutable_name()->append(usage.process_name()).append(", ");

[Sergey Ulanov, 2017/04/03 23:50:21]

nit: it would be cleaner to assemble the aggregate name into a local string
variable and then set it using set_name()

[Hzj_jie, 2017/04/05 20:52:17]

Done. Also updated other variables.

+    aggregated.set_processor_usage(aggregated.processor_usage() +
+                                   usage.processor_usage());
+    aggregated.set_working_set_size(aggregated.working_set_size() +
+                                    usage.working_set_size());
+    aggregated.set_pagefile_size(aggregated.pagefile_size() +
+                                 usage.pagefile_size());
+    *aggregated.add_usages() = usage;
+  }
+  aggregated.mutable_name()->append(" }");
+  return aggregated;
+}
+
+}  // namespace remoting