Chrome Version: (copy from chrome://version)67.0.3396.79
OS: (e.g. Win10, MacOS 10.12, etc...) Mac OS 10.13.4

What steps will reproduce the problem?
(1) Create a calendar event with default notification reminder (say 10 min?) or customize it to alert for 1 min (for testing purpose)
(2) Wait until the calendar notification pops-up on the right side panel 

What is the expected result?
You should be able to hear audio.

What happens instead?
Notification just pops-up silently with no sound.



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For graphics-related bugs, please copy/paste the contents of the about:gpu
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