chromium/content/browser/site_instance_group_manager.h

// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_SITE_INSTANCE_GROUP_MANAGER_H_
#define CONTENT_BROWSER_SITE_INSTANCE_GROUP_MANAGER_H_

#include "base/memory/raw_ptr.h"
#include "content/public/browser/render_process_host_observer.h"

namespace content {

class RenderProcessHost;
class SiteInstanceImpl;

// Policy class that manages groups of SiteInstances and controls whether
// they share a process and/or need to use proxies to communicate with each
// other. This decouples the process model from the SiteInfo granularity used
// by SiteInstances. There are three supported modes:
// 1) SiteInstances placed in the same group will share a process and will not
//    use proxies to communicate with other members of the same group.
// 2) SiteInstances can be placed in different groups, but still share a
//    process. These SiteInstances will use proxies to communicate with frames
//    in the same process as well as cross process frames.
// 3) SiteInstances that require a dedicated process will always be placed in
//    their own group and given a process that is not shared with other
//    principals (i.e., SiteInfos).
//
// This policy object is owned by a BrowsingInstance and the groups it manages
// only contain SiteInstances associated with that BrowsingInstance.
//
// TODO: Update description to include details about when/how SiteInstances
// get assigned to groups. Currently this object only holds the logic for the
// 'default process' model which implements mode 2 mentioned above for any
// SiteInstance that does not require a dedicated process.
class SiteInstanceGroupManager final : private RenderProcessHostObserver { … };
}  // namespace content

#endif  // CONTENT_BROWSER_SITE_INSTANCE_GROUP_MANAGER_H_