[Memory-UMA] Implement basic working prototype.

services/resource_coordinator/memory/coordinator/process_map.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 SERVICES_RESOURCE_COORDINATOR_MEMORY_COORDINATOR_PROCESS_MAP_H_
+#define SERVICES_RESOURCE_COORDINATOR_MEMORY_COORDINATOR_PROCESS_MAP_H_
+
+#include <map>
+#include <vector>
+
+#include "base/gtest_prod_util.h"
+#include "base/hash.h"
+#include "base/process/process_handle.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "services/resource_coordinator/public/interfaces/memory/memory_instrumentation.mojom.h"
+#include "services/service_manager/public/cpp/identity.h"
+#include "services/service_manager/public/interfaces/service_manager.mojom.h"
+
+namespace service_manager {
+class Connector;
+}
+
+namespace memory_instrumentation {
+
+// Maintains a map from service_manager::Identity to base::ProcessId by
+// listening for connections. This allows |pid| lookup by
+// service_manager::Identity.
+class ProcessMap : public service_manager::mojom::ServiceManagerListener {
+ public:
+  explicit ProcessMap(service_manager::Connector* connector);
+  ~ProcessMap() override;
+
+  base::ProcessId GetProcessId(service_manager::Identity identity) const;
+
+ protected:
+ private:
+  FRIEND_TEST_ALL_PREFIXES(ProcessMapTest, TypicalCase);
+  FRIEND_TEST_ALL_PREFIXES(ProcessMapTest, PresentInInit);
+
+  using RunningServiceInfoPtr = service_manager::mojom::RunningServiceInfoPtr;
+
+  // Overridden from service_manager::mojom::ServiceManagerListener:
+  void OnInit(std::vector<RunningServiceInfoPtr> instances) override;
+
+  void OnServiceCreated(RunningServiceInfoPtr instance) override;
+
+  void OnServiceStarted(const service_manager::Identity& identity,
+                        uint32_t pid) override;
+  void OnServiceFailedToStart(
+      const service_manager::Identity& identity) override {}
+
+  void OnServiceStopped(const service_manager::Identity& identity) override;
+
+  mojo::Binding<service_manager::mojom::ServiceManagerListener> binding_;
+  std::map<service_manager::Identity, base::ProcessId> instances_;
+
+  DISALLOW_COPY_AND_ASSIGN(ProcessMap);
+};
+
+}  // namespace memory_instrumentation
+#endif  // SERVICES_RESOURCE_COORDINATOR_MEMORY_COORDINATOR_PROCESS_MAP_H_