DOMTimer currently uses a mix of millisecond (was int, now std::chrono) and second (as double) time values. Constant conversion back and forth is a complete mess. Stop that.
Created attachment 273129 [details] Fix
Created attachment 273161 [details] Fix
Created attachment 273164 [details] Fix
Comment on attachment 273164 [details] Fix r=me, sweet
Transmitting file data .................. Committed revision 197690.