1614871 - [Fission] non-Windows ProxyAccessible::ChildAtPoint needs to cross process boundaries into OOP iframes

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect, P3)

Description

[Eitan Isaacson [:eeejay]]

Currently, the proxy accessible will only query its own DocAccessibleChild for the deepest child. We need to allow proxies to dig into child documents as well.

Comment 1

[James Teh [:Jamie]]

It just occurred to me: won't this be broken for any iframe, not just Fission iframes?

1. Does Accessible::ChildAtPoint traverse into in-process subdocuments? If not, it'll stop at the iframe OuterDoc.
2. Even if it does, it'll return an id from the iframe document. ProxyAccessible will then try to use its own DocAccessibleParent... but it'll be the wrong document.

Comment 2

[James Teh [:Jamie]]

(In reply to James Teh [:Jamie] from comment #1)

1. Does Accessible::ChildAtPoint traverse into in-process subdocuments?

It does:
https://searchfox.org/mozilla-central/rev/7e92a667e3829831c31e8d46aefe7ef67ad5be1c/accessible/generic/OuterDocAccessible.cpp#99

2. Even if it does, it'll return an id from the iframe document. ProxyAccessible will then try to use its own DocAccessibleParent... but it'll be the wrong document.

I wonder if PDocAccessible::AccessibleAtPoint can return a PDocAccessible as well as an id? That will fix the e10s case, but we'll still need code in ProxyAccessible to deal with the recursion for the Fission case.

Comment 3

[James Teh [:Jamie]]

Attachment: Bug 1614871 part 1: Make non-Windows ProxyAccessible::ChildAtPoint cross into in-process iframes.

Accessible::ChildAtPoint can return an Accessible in a descendant document.
Thus, we must return the result PDocAccessible via IPC, not just the id.
Previously, we only returned the id, but we'd fail when we tried to look it up if it belonged to a descendant document.

Comment 4

[James Teh [:Jamie]]

Attachment: Bug 1614871 part 2: Make non-Windows ProxyAccessible::ChildAtPoint cross into OOP iframes.

When we hit an OOP iframe, we must walk into the child document and continue the search from there.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0f241c48730c
part 1: Make non-Windows ProxyAccessible::ChildAtPoint cross into in-process iframes. r=eeejay
https://hg.mozilla.org/integration/autoland/rev/4615751fc827
part 2: Make non-Windows ProxyAccessible::ChildAtPoint cross into OOP iframes. r=eeejay

Comment 6

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/mozilla-central/rev/0f241c48730c
https://hg.mozilla.org/mozilla-central/rev/4615751fc827

Comment 7

[James Teh [:Jamie]]

Eitan, you should hopefully now be able to hit test on both normal (in-process) and Fission (out-of-process) iframes on Mac. Would you be able to test and let me know if it works? Thanks.

Comment 8

[Eitan Isaacson [:eeejay]]

Tested with Accessibility Inspector on Nightly on OSX. Hittesting works inside of embedded youtube videos.

Thanks!