A whole DOM text node was one indivisible taffy leaf. Flex-wrap only
breaks between items, never inside one, so a long run of plain text
with no inline element breaking it up (an ordinary sentence with no
link in it) either fit on one line or ran straight past the
container's edge instead of wrapping. Short runs interrupted by links
every few words (extremely common in Wikipedia's markup) happened to
be narrow enough to wrap on their own, which is why paragraphs looked
fine but any long plain-text stretch overflowed straight over the
infobox and the History-section image.
Text nodes now split into one taffy leaf per word, flattened into the
same child list as sibling elements so words from different text nodes
and inline elements interleave and wrap together like real inline
flow. This changes the geometry data model: a text node's content is
now a list of (box, word) pairs (DomLayout::text_runs) instead of a
single box, since it can span several lines. Updated painting to draw
each word at its own position, and fixed a bold-text measurement
mismatch (layout width and drawn width disagreed by 1px/char, invisible
before as one blob, visible as gaps between every word once each word
is independently positioned).
Added a regression test that fails against the old single-leaf
behavior.
SGavrl
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