Fix overconstrained behaviour for position: sticky.

Ignore one of sticky offsets if both opposite offsets are specified and sum of
opposite offsets is bigger than corresponding dimension of containing block.

BUG=370632

Review URL: https://codereview.chromium.org/267063007

git-svn-id: svn://svn.chromium.org/blink/trunk@174678 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix oilpan build after animation changes.

TBR=haraken@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/291823008

git-svn-id: svn://svn.chromium.org/blink/trunk@174679 bbb929c8-8fbe-4397-9dbb-9b2b20218538