Split positionAndLayoutFloat() off positionNewFloats().

Float layout is somewhat broken when it comes to fragmentation (multicol,
printing). We're going to have to make sure that we always position the
float before laying it out, and, after layout, insert a break before it if
needed. This is a preparatory CL for that.

We currently lay out a float e.g. in insertFloatingObject() without
worrying about setting the position first.

No behavior changes intended.

BUG=663942

Review-Url: https://codereview.chromium.org/2486413002
Cr-Commit-Position: refs/heads/master@{#431422}
2 files changed