This patch puts in the initial framework for incremental reflow. Nodes' styles
are no longer recalculated unless the node has changed.
I've been hacking on the general problem of incremental reflow for the past
couple weeks, and I've yet to get a full implementation that actually passes all
the reftests + wikipedia + cnn. Therefore, I'm going to try to land the different
parts of it one by one.
This patch only does incremental style recalc, without incremental flow
construction, inline-size bubbling, reflow, or display lists. Those will be coming
in that order as I finish them.
At least with this strategy, I can land a working version of incremental reflow,
even if not yet complete.
r? @pcwalton
I converted them all with a few exceptions:
- Methods that were used by trait objects, since trait objects don't
work with `self` methods.
- Methods that take an &'b JSRef<'a, T> and return an &'b. In reality,
many (all?) could return an &'a instead, but this isn't allowed by the
Deref trait.
- Methods that internally rely on the same issue with Deref.
- I left out the traits involved in layout entirely, even though not all
of their methods suffer from one of the above problems.
There will probably be solutions to all of these problems in the future.
Replace &JSRef with JSRef in the bulk of the generated code. This will
remove a level of indirection throughout all DOM code.
This patch doesn't change methods implemented on JSRef<T> to take `self`
rather than `&self`, and it leaves a few other uses of &JSRef, but those
changes can be made incrementally.
For safe wrappers over JS<T> (eg Temporary<T>) use #[allow(unrooted_must_root)].
For all other types containing a #[must_root] value, annotate the type with #[must_root] to ensure that it is never used unrooted
