The idea is to be able to call the right function during style resolution time
without doing a linear walk via nsCSSAnonBoxes::IsNonInheritingAnonBox.
MozReview-Commit-ID: JKt33GggTjz
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extra : rebase_source : fcf477dcef8529c803bf97b1d3a16f8f4fcea39f
The basic idea here is as follows:
* Rule nodes are reference-counted, but releasing them adds them to a linked
list rather than freeing them. This allows for the reuse that motivated the
original GC scheme.
* We get rid of the marking, and instead rely on the reference count.
* Sweeping no longer requires a complicated traversal. We just pop items
off the free list until it's empty. When a child is destroyed, its parent
may go onto the free list.
* We remove special handling for the root node, and use a regular reference-counted
edge from the style set.
* The free list automatically asserts that it's empty (meaning all nodes have been
freed) in its destructor, which runs when the style set is destroyed.
* We get rid of the list of style context roots on the style set. We still need
a count though, because of the HasCachedStyleData check.
Xidorn Quan
Boris Zbarsky
Bobby Holley
Cameron McCormack
Xidorn Quan