Don't use canCollapseAnonymousBlockChild() to determine whether to truncate text.
Doing that happened to do exactly what we wanted, but that seems like a rather
haphazard way of determining it.
We want to truncate text for block containers [1]. That's LayoutBlockFlow.
Additionally, in Blink, HTML button is implemented using LayoutFlexibleBox
(although the web insists that it too is a block container).
[1] https://www.w3.org/TR/css-ui-3/#propdef-text-overflow
Rather than manually testing for isLayoutBlockFlow() || isLayoutButton()
directly when deciding to truncate or not, I went and hijacked
canHaveFirstLineOrFirstLetterStyle(), and renamed it to behavesLikeBlockContainer().
Review-Url: https://codereview.chromium.org/1970183002
Cr-Commit-Position: refs/heads/master@{#393354}
7 files changed
