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

remoting/proto/process_stats.proto

Index: remoting/proto/process_stats.proto
diff --git a/remoting/proto/process_stats.proto b/remoting/proto/process_stats.proto
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+// 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.
+
+// Protocol for process resource usage.
+
+syntax = "proto2";
+
+option optimize_for = LITE_RUNTIME;
+
+package remoting.protocol;
+
+// The resource usage of a single process.
+// Next Id: 5
+message ProcessResourceUsage {
+  // The name or friendly name of the process.
+  optional string process_name = 1;
+
+  // The processor usage. It should be a consistent value on all platforms in
+  // range of 0 to (100 * NumCPUCores).
+  optional double processor_usage = 2;
+
+  // Memory usage of working set.
+  optional uint64 working_set_size = 3;
+
+  // Memory usage of page file.
+  optional uint64 pagefile_size = 4;
+}
+
+// The resource usage of several processes.
+// Next Id: 6
+message AggregatedProcessResourceUsage {
+  // A friendly name of the processes current instance aggregated from.
+  optional string name = 1;
+
+  // The total processor usage.
+  optional double processor_usage = 2;
+
+  // The total memory usage of working set.
+  optional uint64 working_set_size = 3;
+
+  // The total memory usage of page file.
+  optional uint64 pagefile_size = 4;
+
+  // The process resource usage of each individual process.
+  repeated ProcessResourceUsage usages = 5;
+}