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

remoting/host/process_stats_util.cc

Index: remoting/host/process_stats_util.cc
diff --git a/remoting/host/process_stats_util.cc b/remoting/host/process_stats_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b87402fdff5c730d4764a0827a01c2a83d6abfc3
--- /dev/null
+++ b/remoting/host/process_stats_util.cc
@@ -0,0 +1,56 @@
+// 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/host/process_stats_util.h"
+
+#include <stdint.h>
+
+#include <string>
+#include <utility>
+
+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;
+  }
+
+  std::string name = "aggregate { ";
+  double processor_usage = 0;
+  uint64_t working_set_size = 0;
+  uint64_t pagefile_size = 0;
+  protocol::AggregatedProcessResourceUsage aggregated;
+  for (const auto& usage : usages) {
+    name.append(usage.process_name()).append(", ");
+    processor_usage += usage.processor_usage();
+    working_set_size += usage.working_set_size();
+    pagefile_size += usage.pagefile_size();
+    *aggregated.add_usages() = usage;
+  }
+  name += " }";
+  aggregated.set_name(std::move(name));
+  aggregated.set_processor_usage(processor_usage);
+  aggregated.set_working_set_size(working_set_size);
+  aggregated.set_pagefile_size(pagefile_size);
+
+  return aggregated;
+}
+
+}  // namespace remoting