In the future, WebKit will not use two vectors of offsets to store snap offset info. In order to prepare for this, it can instead pass around the pre-existing SnapOffsetsInfo which abstracts away how snap points are stored. This bug tracks using SnapOffsetsInfo to a greater extent and removing references to "horizontal snap offsets" and "vertical snap offsets."
Created attachment 414902 [details]
Created attachment 414904 [details]
Created attachment 414905 [details]
Created attachment 414906 [details]
Comment on attachment 414906 [details]
I'm going to split these changes up into smaller pieces that are easier to review. Sorry for the noise.
I'm going to close this metabug in favor of using bug 145157 as the metabug, just to make chasing these a bit easier.
*** This bug has been marked as a duplicate of bug 145157 ***