gl_context_glx: Do not use core profile on Mesa Optimus

gl_context_glx: Do not use core profile on Mesa Optimus

This patch hardcodes the workaround detection as it is needed at OpenGL
context creation time.

BUG=659030

[Zhenyao Mo, 2016-10-28 21:37:19]

zmo@chromium.org changed reviewers:
+ zmo@chromium.org

[Zhenyao Mo, 2016-10-28 21:37:19]

I prefer to go down the path of adding a gpu driver bug workaround
(disable_gl_core_profile) and add an entry for mesa with optimus. That way we
can apply it to other problematic platforms and easy to disable (in the future
when the issue is fixed)

[Corentin Wallez, 2016-10-29 01:57:02]

On 2016/10/28 at 21:37:19, zmo wrote:
> I prefer to go down the path of adding a gpu driver bug workaround
(disable_gl_core_profile) and add an entry for mesa with optimus. That way we
can apply it to other problematic platforms and easy to disable (in the future
when the issue is fixed)

The problem is that we need to create a GL context to know it is Mesa, which we
need to have the workaround, which we need to create a GL context.