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
Backed out 4 changesets (bug 826148) because of test failures

Backed out changeset e520c411aed6 (bug 826148)
Backed out changeset 1db5b4e59649 (bug 826148)
Backed out changeset 57bf735f3e18 (bug 826148)
Backed out changeset b659dc17b164 (bug 826148)
Bug 829180 - Never open externally opened links in a private window; r=gavin
Bug 588237, patch 2:  Fix comment that is now incorrect due to work in bug 563584 or followups.  r=roc
Bug 588237, patch 3:  Remove the pushed floats list when it is empty.  r=roc
Bug 588237, patch 4:  Pull pushed floats back from the next-in-flow at the start of reflow.  r=roc
Bug 588237, patch 5:  remove the optimization of skipping FlowAndPlaceFloat for some pushed floats, simply because the optimization looks fishy to me.  r=roc
Bug 827698:  Use the length of the 'animation-name' list when determining how many animations to run.  r=bzbarsky

NOTE:  The tests in test_animations.html fail without the patch; the
tests in test_shorthand_property_getters.html are only tangentially
related and pass both with and without the patch.
Bug 827717:  Change record of CSS animation start to be before delay so that dynamic changes to animation-delay are honored.  r=bzbarsky

This matches the CSS Working Group consensus recorded in
http://lists.w3.org/Archives/Public/www-style/2012Nov/0261.html , though
the spec hasn't yet been updated.
Bug 827687:  Fix edge case in calculation of whichIteration.  r=bzbarsky
Bug 827687, patch 2:  Be more careful walking segments.  r=bzbarsky
Merge mozilla-central into mozilla-inbound