[css-animationworklet] Migrate repository from WICG to Houdini Drafts

[majido]

In Berlin F2F, WG resolved to move animation worklet specification to Houdini drafts. This issue is meant to help track any work that needs to happen for the move.

[majido]

My aim to migrate the repository without losing any of the history. Git properly handler merging two unrelated repositories in a single commit which ensure the final commit carries both histories.

Merge

Most merge commits have a diamond shape where one side is branch from the main branch at some earlier point but it is possible to merge to branches that don't share an ancestor. This is what I am proposing to do here.

Here is the series of commands I will be using:

$ cd css-houdini-drafts
$ git remote add wicg git@github.com:WICG/animation-worklet.git
$ git fetch wicg
$ git checkout -b wicg wicg/gh-pages
$ mkdir css-animationworklet
$ mv * css-animationworklet/
$ git add .
$ git commit -m "Move to sub-directory in preparation to repo migration"
$ git checkout master 
$ git merge --allow-unrelated-histories wicg

Here is the resulting commit for example.

I can them make PR and that can be merged to the main repo without squashing or rebasing.

Post merge

I think it is best to move the repository with minimum require change (i.e., only move to
sub-directory).

Once repository is merged in css-houdini-drafts I will followup with these cleanups:

• Remove redundant w3c.json, CONTRIBUTING, LICENSE
• Use correct name and URL in the spec and README
• rename index.bs to Overview.bs

[majido]

@bfgeek does this plan sound reasonable? Also are you able to approve and merge the PR request once I make it?