cogl_framebuffer_add_fence creates a synchronisation fence, which will
invoke a user-specified callback when the GPU has finished executing all
commands provided to it up to that point in time.
Support is currently provided for GL 3.x's GL_ARB_sync extension, and
EGL's EGL_KHR_fence_sync (when used with OpenGL ES).
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Reviewed-by: Neil Roberts <neil@linux.intel.com>
Reviewed-by: Robert Bragg <robert@linux.intel.com>
https://bugzilla.gnome.org/show_bug.cgi?id=691752
(cherry picked from commit e6d37470da9294adc1554c0a8c91aa2af560ed9f)
