1437994 - (browsingcontext) Implement Browsing Context

Status: RESOLVED FIXED

(Core :: DOM: Navigation, enhancement, P2)

Description

[Nika Layzell [:nika] (ni? for response)]

Our plans for site isolation include the need to add out-of-process iframe support as well as the ability for every docshell to migrate between processes at runtime. This means that we will need the ability to access, traverse, and reference docshell trees which have docshells spread across multiple processes.

This bug is to track the implementation of this mechanism. I have thought of a few options for how we could do this, which we will need to investigate:

1. Create "real" nsDocShell objects in all processes forming a docshell tree, and set a flag on them to signify that they are out of process. This would allow us to transition a docshell into process without breaking references, but has the disadvantage of not using the type system to ensure we don't call methods or attempt to manipulate an out-of-process docshell.

2. Create "fake" nsIDocShellTreeItem objects, and replace them in the tree when they are moved into or out of process. This will mean that we will need to ensure references to docshells are not held between navigations, as those references could break.

3. Create a new tree which is synchronized across processes, and change nsIDocShellTreeItem operations to act on this tree. Only dangle nsDocShell objects off of the items in the tree which are in process, and generally prefer to hold references to the in-tree objects when references must be held across loads.