Introduce IntrinsicSizingInfo

Prepare for passing more information along, specifically whether
intrinsic sizes are specified, when computing intrinsic sizing
information. Do this by introducing a struct carrying the relevant
information. No functional change expected.

Factor out a part of computeAspectRatioInformationForLayoutBox (now
named computeIntrinsicSizingInfoForLayoutBox) and put in a separate
function constrainIntrinsicSizeToMinMax. In the process remove a FIXME
about moving code back to some undefined previous state that's
confusing now that the code has moved around even more.

BUG=585467

Review URL: https://codereview.chromium.org/1687503002

Cr-Commit-Position: refs/heads/master@{#374635}
8 files changed