Remove detection of the GLX_SGIX_fbconfig extension, this is not what we need to detect availability of the glx create/destroy pixmap hooks. Instead, make it conditional on texture_from_pixmap.

BUG=None
TEST=Compile and run the window manager, should work as usual both on real hardware an inside the virtual machine (they exercise the two codepaths).

Review URL: http://codereview.chromium.org/6814022

Change-Id: I4f140e079402244e5d93a71ff411357f32fe4437
1 file changed