This CL adds the callback on changes of the ICE connection state following the standardized transitions (https://www.w3.org/TR/webrtc/#dom-rtciceconnectionstate) to the Android and the iOS SDKs. Bug: None Change-Id: I6133391fa54dd4e09016f29dddb85e4a0e270878 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/138181 Reviewed-by: Kári Helgason <kthelgason@webrtc.org> Reviewed-by: Steve Anton <steveanton@webrtc.org> Reviewed-by: Amit Hilbuch <amithi@webrtc.org> Reviewed-by: Alex Glaznev <glaznev@webrtc.org> Commit-Queue: Qingsi Wang <qingsi@webrtc.org> Cr-Commit-Position: refs/heads/master@{#28127}