In our current implementation the implicit grid is only after the explicit grid. For example, in a 2x2 grid, if you have an item with: grid-row: 3; An implicit 3rd row is created. However, if you have an item like: grid-column: -4; We should be creating an implicit column before the first one. This has been already implemented on Blink (http://crbug.com/444011) following a plan described in this document (http://bit.ly/1j3CRdi). We should port these patches to WebKit as the grid layout code has the same issues. This will be used as meta-bug for all the patches related. More info in the spec: http://dev.w3.org/csswg/css-grid/#line-placement
We've a TODO in GridResolvedPosition class: // TODO(rego): Rename class to GridPositionsResolver. This was already done in Blink: https://codereview.chromium.org/1648903002/
(In reply to comment #1) > We've a TODO in GridResolvedPosition class: > // TODO(rego): Rename class to GridPositionsResolver. > > This was already done in Blink: > https://codereview.chromium.org/1648903002/ Sorry this comment was for bug #155486.
With the last refactorings this task has been completed.