[Memory-UMA] Implement basic working prototype.

services/resource_coordinator/memory/coordinator/process_map.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 "services/resource_coordinator/memory/coordinator/process_map.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/connector.h"
+#include "services/service_manager/public/cpp/identity.h"
+#include "services/service_manager/public/interfaces/constants.mojom.h"
+#include "services/service_manager/public/interfaces/service_manager.mojom.h"
+
+namespace memory_instrumentation {
+
+ProcessMap::ProcessMap(service_manager::Connector* connector) : binding_(this) {
+  if (connector) {
+    service_manager::mojom::ServiceManagerPtr service_manager;
+    connector->BindInterface(service_manager::mojom::kServiceName,
+                             &service_manager);
+    service_manager::mojom::ServiceManagerListenerPtr listener;
+    service_manager::mojom::ServiceManagerListenerRequest request(
+        mojo::MakeRequest(&listener));
+    service_manager->AddListener(std::move(listener));
+
+    binding_.Bind(std::move(request));
+  }
+}
+
+ProcessMap::~ProcessMap() {}
+
+void ProcessMap::OnInit(std::vector<RunningServiceInfoPtr> instances) {
+  // This callback should only be called with an empty model.
+  DCHECK(instances_.empty());
+  for (size_t i = 0; i < instances.size(); ++i) {
+    const service_manager::Identity& identity = instances[i]->identity;
+    instances_.emplace(identity, instances[i]->pid);
+  }
+}
+
+void ProcessMap::OnServiceCreated(RunningServiceInfoPtr instance) {
+  if (instance->pid == base::kNullProcessId)
+    return;
+
+  const service_manager::Identity& identity = instance->identity;
+  DCHECK(instances_.find(identity) == instances_.end());
+  instances_.emplace(identity, instance->pid);
+}
+
+void ProcessMap::OnServiceStarted(const service_manager::Identity& identity,
+                                  uint32_t pid) {
+  instances_[identity] = pid;
+}
+
+void ProcessMap::OnServiceStopped(const service_manager::Identity& identity) {
+  instances_.erase(identity);
+}
+
+base::ProcessId ProcessMap::GetProcessId(
+    service_manager::Identity identity) const {
+  auto instance = instances_.find(identity);
+  if (instance == instances_.end())
+    return base::kNullProcessId;
+  return instance->second;
+}
+
+}  // namespace memory_instrumentation