The ENABLE(CSS_IMAGE_ORIENTATION) guard is present in the source base, but does not appear to be used by any active WebKit ports.
We should either activate and begin testing this feature, or remove the code.
I promised to remove this feature by July 17, 2013 but have clearly not done so!
I plan on doing so this week.
Since the work in Bug 92330 is finished, does that mean the ENABLE_CSS_IMAGE_ORIENTATION is in active use? If so, I'll close this bug.