Current spec for CaretPosition interface has a caret range concept which is a live range. The caret range is only used to get the client rect of the CaretPosition. We should avoid creating the live range upfront because:

1. the live range is not used at all except for getting client rect.
2. Maintain live range can be expensive during DOM mutation.
3. No browsers implemented the algorithm by creating live range upfront. (Firefox and Chromium both create a live range only when CaretPosition::getClientRect() is invoked.)

Propose to remove caret range concept from CaretPosition interface.