Chrome Version: 69.0.3497.35 (Official Build) dev (64-bit)
OS: ChromeOS

What steps will reproduce the problem?
1) Have more than one notification 
2) Use Shift+Alt+N to open the notification panel 
3) Hit tab to focus on the first notification 
4) Hit Backspace to dismiss the first notification 
5) This will highlight/focus the next notification 
6) Hit backspace again 

What is the expected result? 
The next notification is dismissed

What happens instead?
Everything crashes



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