With this change, we now have ~1200 CellAllocators across both LibJS and
LibWeb in a normal WebContent instance.
This gives us a minimum heap size of 4.7 MiB in the scenario where we
only have one cell allocated per type. Of course, in practice there will
be many more of each type, so the effective overhead is quite a bit
smaller than that in practice.
I left a few types unconverted to this mechanism because I got tired of
doing this. :^)
This only tracks whether the relevant steps should be executed at some
future (but very soon) time. This time will eventually be whenever the
"update animations and send events" procedure is invoked.
This is mostly a copy-paste of the algorithms already in StyleComputer
with spec links and comments. The only thing that really changed is the
handling of values outside of the range [0, 1] in the cubic bezier
function.
The implementation in StyleComputer will be removed in a later commit.
This is split into two functions since there are other places in the
specification that invoke this algorithm with a particular FillMode
(i.e. not the one that the object has in m_fill_mode).
This will be required for propagating the current animation time to all
relevant timelines, which each propagate that time to all of their
relevant animations.
