[Memory-UMA] Add ProcessMap, an Identity to Pid map

services/resource_coordinator/memory/coordinator/process_map.cc

Index: services/resource_coordinator/memory/coordinator/process_map.cc
diff --git a/services/resource_coordinator/memory/coordinator/process_map.cc b/services/resource_coordinator/memory/coordinator/process_map.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2b2e610c53163f0b8563687e13ac9e007881df3b
--- /dev/null
+++ b/services/resource_coordinator/memory/coordinator/process_map.cc
@@ -0,0 +1,60 @@
+// 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/identity.h"
+#include "services/service_manager/public/interfaces/service_manager.mojom.h"
+
+namespace memory_instrumentation {
+
+ProcessMap::ProcessMap(
+    service_manager::mojom::ServiceManagerListenerRequest request)
+    : binding_(this, 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) {
+  service_manager::Identity identity = instance->identity;
+  // The instance should not already exists
+  DCHECK(instances_.find(identity) == instances_.end());
+  instances_.emplace(identity, instance->pid);
+}
+
+void ProcessMap::OnServiceStarted(const service_manager::Identity& identity,
+                                  uint32_t pid) {
+  auto instance = instances_.find(identity);
+  if (instance != instances_.end()) {
+    instance->second = pid;
+  }
+}
+
+void ProcessMap::OnServiceStopped(const service_manager::Identity& identity) {
+  auto instance = instances_.find(identity);
+  DCHECK(instance != instances_.end());
+  instances_.erase(instance);
+}
+
+base::ProcessId ProcessMap::GetProcessId(
+    service_manager::Identity identity) const {
+  auto instance = instances_.find(identity);
+  if (instance == instances_.end())
+
+    return base::kNullProcessHandle;
+  return instance->second;
+}
+
+}  // namespace memory_instrumentation