1597511 - Audit nsIDocShellTreeItem usage in mozilla::AppWindow::Initialize in xpfe/appshell/AppWindow.cpp

Status: NEW

(Core :: Window Management, defect, P3)

Description

[Kannan Vijayan [:djvj]]

In file xpfe/appshell/AppWindow.cpp

Just sets the TreeOwner for a DocShell.

Later: checks the itemType of a DocShell, which can be changed to check ItemType of associated BrowsingContext.

Marker bug - this should go away when the docshell tree goes away.

Comment 1

[Chris Peterson [:cpeterson]]

Kannan says replacing nsIDocShellTreeItem calls should block enabling Fission in Nightly (M6).

Comment 2

[Chris Peterson [:cpeterson]]

Moving to Window Management component.

Please audit this use of the nsIDocShellTreeItem interface. With Fission enabled, Documents and nsDocShells for related frames, such as subframes and parent documents, may not be available within the current process and the corresponding nsIDocShellTreeItem methods will return null

If this code works as-is with Fission, we don't need to remove this usage of nsIDocShellTreeItem until when we remove nsIDocShellTreeItem entirely (bug 1607591) after we ship Fission MVP.

Fission documentation about replacing nsIDocShellTree Item:
https://wiki.mozilla.org/Project_Fission/DocShell_Tree_Replace

:farre's presentation with examples of replacing nsIDocShellTreeItem with BrowsingContext, WindowContext, SyncedContexts, and BrowsingContextGroup:
https://docs.google.com/presentation/d/1K4j6ngty64TZjJNS5qH-MBoOm3TI2dJedVsbH8jUhKE/edit#slide=id.g6e35225e5d_1_264

Comment 3

[Chris Peterson [:cpeterson]]

Neil, someone with appshell experience will need to triage this bug and audit this code for Fission.

Comment 4

[Neil Deakin]

AppWindow is only created in the parent process as far as I know. In fact, the code in AppWindow::Initialize assumes it is a chrome window.