Google Chrome	69.0.3497.21 (Official Build) dev (64-bit)
Firmware Version	Google_Lulu.6301.136.57

First, I'll clarify the expected and actual in M69 for "two live region changes, one second apart"

# Turn on ChromeVox with ctrl + alt + z 
# Navigate to  https://minorninth.github.io/aria-live-region-tests/live_region_tests.html
# Navigate to "<button>two live region changes, one second apart</button>"
# Invoke it with Enter.
Expected, two parts: First, this text will be interrupted by the second utterance before it finishes: 
"This utterance should be interrupted before it finishes"
Then, part two, ChromeVox will say "Live region succeeded"

Actual: 
ChromeVox says one after another "This utterance should be interrupted before it finishes" and then "Live region succeeded." The second one did not interrupt the first as expected. 

(this is split off of  bug 869576 )