[New Multicolumn] Intrinsic/preferred logical width calculation for spanners.
Need to skip multicol adjustment of preferred widths when it comes to spanners.
Their preferred widths should not be multiplied by the number of columns.
Conversely, when encountering column-span:all renderers somewhere inside flow
threads, for preferred width calculation, skip them, since they're not column
content.
When a multicol container asks a child spanner placeholder about its preferred
logical width, relay to the actual column-span:all renderer.
BUG=347325
R=jchaffraix@chromium.org
Review URL: https://codereview.chromium.org/879483002
git-svn-id: svn://svn.chromium.org/blink/trunk@189030 bbb929c8-8fbe-4397-9dbb-9b2b20218538
14 files changed
