[webcomponents] Add 'delegatesFocus' proposal. (#272)

Please pull this again to restore the proposal file.
You can view, comment on, or merge this pull request online at:

  https://github.com/w3c/webcomponents/pull/272

-- Commit Summary --

  * Add 'delegatesFocus' proposal.

-- File Changes --

    A proposals/ShadowRoot-delegatesFocus-Proposal.md (59)

-- Patch Links --

https://github.com/w3c/webcomponents/pull/272.patch
https://github.com/w3c/webcomponents/pull/272.diff

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Reply to this email directly or view it on GitHub:
https://github.com/w3c/webcomponents/pull/272