UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36

Steps to reproduce the problem:
1. Hover cursor over each div containing a button

What is the expected behavior?
The background-size of each div should transition to 100% width.

What went wrong?
Some divs that have certain styles applied to their child button prevent the new background-size from painting.

Did this work before? Yes 

Does this work in other browsers? Yes

Chrome version: 61.0.3163.100  Channel: stable
OS Version: 10.0
Flash Version: 

Each div has a child button. Each one has a different set of styles applied. Each one changes the background-size of the div when hovered (this bug is also present when styling on changes to attributes or classes, not just hover).

Buttons with the following styles applied prevent painting of the new background-size for their parent div:
border-color: [any value]
background-color: [any value]
display: block + border-width: [any value]

For those divs exhibiting this bug, when clicking a button, the correct background-size will be painted and continue to work correctly until clicking elsewhere. Manually applying :focus in dev tools does not appear to influence this behaviour.

This bug is not currently present in IE 11, Edge, Firefox or Safari.

I'm not entirely sure when this regressed as it took a while to reduce to this test case, but it was definitely functioning correctly at one time (sometime after the fork from WebKit).
 

Deleted: button-styles-break-parent-background-size-painting.html 2.1 KB

button-styles-break-parent-background-size-painting.html 2.1 KB View Download