In some cases a document may lack an associated window - to fix this for
now we just return false but perhaps there are some media queries we
should still attempt to resolve.
Fixes crash in the created test as well as https://wpt.live/css/css-text
/word-spacing/reference/word-spacing-percent-001-ref.html. The WPT test
hasn't been imported as it passing is currently a false-positive due to
the fact that we don't yet respect `word-spacing` in most cases.
We've historically asserted that no "saturated" size values end up as
final metrics for boxes in layout. This always had a chance of producing
false positives, since you can trivially create extremely large boxes
with CSS.
The reason we had those assertions was to catch bugs in our own engine
code where we'd incorrectly end up with non-finite values in layout
algorithms. At this point, we've found and fixed all known bugs of that
nature, and what remains are a bunch of false positives on pages that
create very large scrollable areas, iframes etc.
So, let's change it! We now clamp content width and height of boxes to
17895700 pixels, apparently the same cap as Firefox uses.
There's also the issue of calc() being able to produce non-finite
values. Note that we don't clamp the result of calc() directly, but
instead just clamp values when assigning them to content sizes.
Fixes#645.
Fixes#1236.
Fixes#1249.
Fixes#1908.
Fixes#3057.
