RTCStatsMemberInterface::Type's kBool and kSequenceBool.
This means that RTCStats-derived classes ("RTCStats-derived
dictionaries"[1]) can contain boolean and sequence of boolean members.
[1] https://w3c.github.io/webrtc-stats/
BUG=chromium:627816
NOTRY=True
Review-Url: https://codereview.webrtc.org/2387343002
Cr-Commit-Position: refs/heads/master@{#14509}