Bug 44352 – AX: CSS first letter text transform causes crash

• Status: RESOLVED
• Resolution: FIXED
• Component: Accessibility

[Chris Guillory]

This bug is causing the chromium renderer to crash.
http://code.google.com/p/chromium/issues/detail?id=52758

A bad type cast is occurring and this might be a regression from r65095.
http://trac.webkit.org/changeset/65095

I've attached a layout tests that reproduces the issue.

[Chris Guillory]

Created attachment 64983 [details]
Layout Tests

[Chris Guillory]

Created attachment 64996 [details]
Another Layout Test

Here's another layout test that reproduces the same issue. DRT crashes if the assert failures are skipped.

This is from http://code.google.com/p/chromium/issues/detail?id=52829.

[chris fleizach]

Created attachment 65003 [details]
Patch

[chris fleizach]

it looks like isInline() is not the right check to use before casting to RenderInline

[Chris Guillory]

Casting to RenderInline or RenderBlock only when exact class type is known. Change looks good to me. Can someone approve. This is currently a top chromium crasher.
http://webkit.org/blog/115/webcore-rendering-ii-blocks-and-inlines

[chris fleizach]

(In reply to comment #5)
> Casting to RenderInline or RenderBlock only when exact class type is known. Change looks good to me. Can someone approve. This is currently a top chromium crasher.
> http://webkit.org/blog/115/webcore-rendering-ii-blocks-and-inlines

Chris, why is accessibility code being run for most people... in general, accessibility code should only be triggered when a screen reader is running

[Chris Guillory]

In general you are correct. However, on certain systems configurations accessibility is being enabled even though no screen reader is in use. On windows tablets the Tablet PC Input Panel program accesses accessibility functions. On mac there are uses of accessibility functions by non screen readers; also if Universal Access System Preferences Pane -> Enable access for assistive devices is checked, accessibility will be on.

I don't think the code is being run by most people. But since the crash occurs with relative ease it shows up often.

[chris fleizach]

(In reply to comment #7)
> On mac there are uses of accessibility functions by non screen readers; also if Universal Access System Preferences Pane -> Enable access for assistive devices is checked, accessibility will be on.

As a FYI, even when this check box is on, accessibility code won't be run unless someone makes an accessibility request (like VoiceOver, Accessibility inspector, or whoever else actually uses accessibility)

[David Kilzer (:ddkilzer)]

Comment on attachment 65003 [details]
Patch

r=me

[chris fleizach]

http://trac.webkit.org/changeset/66061

[WebKit Review Bot]

http://trac.webkit.org/changeset/66061 might have broken SnowLeopard Intel Release (Tests)