Backout bug 828789 (bb755890ec69) because of bug 829335

Backout pixman update.
CLOSED TREE

--HG--
extra : transplant_source : Q%C9%98%DD%A3%83%8CW%22%18k%7B%26VR%8C%5B%FF%91%3E
Merge mozilla-central into mozilla-inbound