1495772 - Add test for scroll bars not triggering the font inflation writing mode assertion

Status: NEW

(Core :: Layout: Text and Fonts, enhancement, P3)

Comment 1

[Jan Henning [:JanH]]

Attachment: Bug 1495772 - Add crash test for font inflation writing mode assertion. r?dbaron

The scroll bars are one special case where a change in writing mode (horizontal
vs. vertical) won't create a new font inflation flow root. This conflicts with
the assertion added in bug 1495772 that the writing mode of a child frame should
always match that of their corresponding font inflation flow root.

Because we don't actually want to inflate the scroll bars, this is fine, but
prior to bug 1495323 margin computation nevertheless calculated font size in-
flation for all frames and would therefore hit the assertion if the HTML element
itself used a non-horizontal writing mode - the scroll bars themselves always
retain the default horizontal writing mode.

We didn't have a test with both a non-horizontal writing mode on the HTML
element and font inflation enabled, so we add one here.

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee is inactive on Bugzilla, so the assignee is being reset.

Comment 3

[Suhaib Mujahid [:suhaib]]

Sorry, there was a problem with the detection of inactive users. I'm reverting the change.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The bug assignee is inactive on Bugzilla, so the assignee is being reset.