UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.167 Safari/537.36

Steps to reproduce the problem:
1. Set a container to "width: fit-content" or "width: max-content"
2. Don't set an explicit width on block child content
3. Observe that the element doesn't fill the space.

What is the expected behavior?
The spec says that fit-content should use the max-content block size up to the finite available space.

The max-content block size algorithm (which is also rendering incorrectly in Chrome) should be "The box’s “ideal” size in the block axis. Usually the block size of the content after layout." - https://www.w3.org/TR/css-sizing-3/#max-content-block-size

What went wrong?
Observe that Firefox calculates fit-content and max-content correctly, by granting block content available space.

Currently, Chrome will artificially "shrink" block-level content when the block is in a container with "fit-content" or "max-content". So, a "display: grid" within fit-content will use, say, half of the available viewport width.

Note that the algorithm is also incorrect for the CSS grid fit-content() CSS function for grid-column-width, which appears to use the same calculation.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 64.0.3282.167  Channel: stable
OS Version: OS X 10.12.6
Flash Version: Shockwave Flash 28.0 r0
 

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