[webrtc-pc] new commits pushed by aboba

The following commits were just pushed by aboba to https://github.com/w3c/webrtc-pc:

* Adding note about when ICE restarts are recommended.

Fixes #1445.
  by Taylor Brandstetter
https://github.com/w3c/webrtc-pc/commit/30baab00fca6f76d46143454984174bf5d7e1420

* Changing to fippo's suggested wording
  by Taylor Brandstetter
https://github.com/w3c/webrtc-pc/commit/da0562cbcf9b3718fb6aacf2389baf3eb621fa3c

* Merge pull request #1910 from taylor-b/issue_1445_when_to_ice_restart

Adding note about when ICE restarts are recommended.
  by Bernard Aboba
https://github.com/w3c/webrtc-pc/commit/824fa214026bdc64b0be91a623bb072cafe1c062