Firefox testing - offscreen surfaces and OMTC

[Martin Stransky]

On 08/24/2015 09:43 AM, drago01 wrote:
> On Mon, Aug 24, 2015 at 8:54 AM, Martin Stransky <stransky at redhat.com> wrote:
>> On 08/21/2015 08:28 PM, Thomas Daede wrote:
>>>
>>> I've been running nightly with this enabled for quite a while on Intel
>>> and it's been fine.
>>>
>>> Note that OMTC is required for e10s.
>>
>>
>> If you mean OMTC by "this" then you're right - it works fine on nightly
>> because nightly is built with in-tree cairo. Fedora it built with system
>> cairo which causes crashes with OMTC enabled. First build which supports
>> in-tree cairo & Gtk3 is FF41.
>
> Why? What's the difference between the in-tree and the system cairo?
> Ist it newer? Older? Patched? Or just built with a different
> configuration?

in-tree cairo is a cairo library intergated in firefox tree, patched for 
mozilla needs and used for internal rendering. system cairo is a cairo 
library shipped in Fedora and used by gtk3 to draw.

ma.