execution_context.h | Explore in Territory

// Copyright 2020 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_EXECUTION_CONTEXT_EXECUTION_CONTEXT_H_
#define COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_EXECUTION_CONTEXT_EXECUTION_CONTEXT_H_

#include "base/observer_list_types.h"
#include "components/performance_manager/public/execution_context_priority/execution_context_priority.h"
#include "third_party/blink/public/common/tokens/tokens.h"

class GURL;

namespace performance_manager {

class FrameNode;
class Graph;
class ProcessNode;
class WorkerNode;

PriorityAndReason;

namespace execution_context {

class ExecutionContextObserver;
class ExecutionContextObserverDefaultImpl;

// The types of ExecutionContexts that are defined.
enum class ExecutionContextType { … };

// An ExecutionContext is a concept from Blink, which denotes a context in
// which Javascript can be executed. Roughly speaking, both FrameNodes and
// WorkerNodes correspond to ExecutionContexts in the PM world-view. This class
// allows external observers to track ExecutionContexts abstractly, without
// having to deal with multiple types at runtime, and duplicating lots of code.
//
// A decorator is responsible for augmenting each instance of a WorkerNode or a
// FrameNode with an instance of ExecutionContext which wraps it, and provides
// accessors for concepts that are common between these two node types. It also
// provides an observer which adapts FrameNodeObserver and WorkerNodeObserver
// behind the scenes, so you don't have to.
//
// Instances of this object are managed by the ExecutionContextRegistry. Their
// lifetimes are the same as those of the underlying nodes they wrap.
class ExecutionContext { … };

// An observer for ExecutionContexts.
class ExecutionContextObserver : public base::CheckedObserver { … };

// A default implementation of ExecutionContextObserver with empty stubs for all
// functions.
class ExecutionContextObserverDefaultImpl : public ExecutionContextObserver { … };

}  // namespace execution_context
}  // namespace performance_manager

#endif  // COMPONENTS_PERFORMANCE_MANAGER_PUBLIC_EXECUTION_CONTEXT_EXECUTION_CONTEXT_H_
chromium/components/performance_manager/public/execution_context/execution_context.h
