This exposes some functions on wr::DisplayListBuilder to set hit-test
info and to do hit-tests.
The mechanism to set hit-test info is made a little more generic than is
actually used in this patchset, because doing it this way allows for
more optimization possibilities.
Specifically, the API allows setting some hit-testing state which is then
applied to all display items that are created until that state is
updated or cleared. An alternative would be to specify the hit-testing
state explicitly when creating particular display items; however doing
that would force the call sites that create the display items to compute
or obtain the hit-testing state, which would make the code less
encapsulated and harder to refactor/optimize.
MozReview-Commit-ID: EJoCFv83iu8
--HG--
extra : rebase_source : d2a117a52144f76dcc312de2a4047298e78135cb
a02e29e13b