am 2427cd61: am 2fb528f4: Adds notes to upstream feature guards added in V8DOMWrapper.cpp.

Merge commit '2427cd61fec29b72e27eb037ca0c6c57cb4ad66c'

* commit '2427cd61fec29b72e27eb037ca0c6c57cb4ad66c':
  Adds notes to upstream feature guards added in V8DOMWrapper.cpp.