chromium/components/performance_manager/public/graph/system_node.h

// Copyright 2019 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_GRAPH_SYSTEM_NODE_H_
#define COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_GRAPH_SYSTEM_NODE_H_

#include "base/memory/memory_pressure_listener.h"
#include "base/observer_list_types.h"
#include "components/performance_manager/public/graph/node.h"

namespace performance_manager {

class SystemNodeObserver;

// The SystemNode represents system-wide state. Each graph owns exactly one
// system node. This node has the same lifetime has the graph that owns it.
class SystemNode : public TypedNode<SystemNode> { … };

// Pure virtual observer interface. Derive from this if you want to be forced to
// implement the entire interface.
class SystemNodeObserver : public base::CheckedObserver { … };

// Default implementation of observer that provides dummy versions of each
// function. Derive from this if you only need to implement a few of the
// functions.
class SystemNode::ObserverDefaultImpl : public SystemNodeObserver { … };

}  // namespace performance_manager

#endif  // COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_GRAPH_SYSTEM_NODE_H_