[css-flexbox] Apply min-height: auto to nested flexboxes again

This was made possible by crrev.com/c/1283482, which avoids the
performance and correctness issues this previously caused.

This relands crrev.com/c/1246730 / crrev.com/c/1252682. The ChromeOS UI
breakage was fixed by crrev.com/c/1281726 and crrev.com/c/1282462

IF THIS BREAKS ANY FURTHER CHROME UI:
Please don't revert this patch; instead, add min-height: 0 to any
inner nested flexboxes that may be affected by this patch. This is
an important change for web interop with the other browsers.

Bug: 596743
Change-Id: I9afe54dce82d41da452d1fdca8150ca22ebb6f9c
Reviewed-on: https://chromium-review.googlesource.com/c/1269235
Commit-Queue: Christian Biesinger <cbiesinger@chromium.org>
Reviewed-by: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/master@{#601540}
3 files changed