Translate flow thread coords to the nearest enclosing coord space when appropriate.
We used to always convert to the visual coordinate space, meaning that we
walked all enclosing fragmentation contexts. However, only the PaintLayer code
wants this behavior, while everyone else typically wants to do one
fragmentation context at a time, e.g. when walking the ancestry with
LayoutObject::mapLocalToAncestor().
For nested multicol, this caused invalidation bugs, problems with
getClientRects(), and maybe more.
Added an enum CoordinateSpaceConversion (with values "Containing" and "Visual")
for flowThreadTranslationAtOffset() to use to determine which conversion to
perform. The old behavior was to always do CoordinateSpaceConversion::Visual.
BUG=604883
Review URL: https://codereview.chromium.org/1907443003
Cr-Commit-Position: refs/heads/master@{#388692}
13 files changed
