More QQuickCanvas cleanup handling.

Avoid calling into QQuickContext2D from QQuickContext2DTexture
after QQuickContext2D has been deleted. We acheive this by

1. Giving the texture a direct pointer to the gl context and
   and surface, so that it doesn't need to go through m_context
   to get to them (which may have been deleted).

2. Protect access to QQuickContext2DTexture::m_context with
   a mutex and make sure it is set to 0 in a safe manner
   when the QQuickContext2D object is deleted.

Change-Id: Ie0a30f9fc46f844224838a7cdf2f28a62e8ce322
Reviewed-by: Laszlo Agocs <laszlo.agocs@digia.com>

0 files changed, 0 insertions, 0 deletions