Proposal for supporting Web Components and Shadow DOM

So we are wanting to start testing applications that are built using Web
Components and therefore require access to the shadow DOM. We would like to
start implementing some of this support in ChromeDriver. However when we
look at the minimal section in the spec that refers to shadow dom, the
proposed API is pretty ugly and incomplete. I have written up a brief
proposal for a replacement in:
https://docs.google.com/document/d/1qP7Se3MDUac5P0V1Kfm2yaj3fFhBOFCyWyXLcsVwkTA/edit?usp=sharing

Please comment.

Marc