Hello,
After I updated to Chrome 66.0.3359.139 I can no longer select text in an alert dialogue.
This appears to occur with alert dialogue's that have multiple lines of text with line breaks (using \n)
I confirmed this worked previous to 66.0.3359.139.
Is this something I can enable via a flag?

| Google Chrome | 66.0.3359.139 (Official Build) (64-bit) |
| Revision | a020eddf0d85fe84d4a6787b304f50aafb670969-refs/branch-heads/3359@{#767} |
| OS | Mac OS X |
| JavaScript | V8 6.6.346.26 |
| Flash | 29.0.0.140 /Users/kevinbroomall/Library/Application Support/Google/Chrome/PepperFlash/29.0.0.140/PepperFlashPlayer.plugin |
| User Agent | Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36 |