min-content drops box decorations on leading whitespace inside an open inline

#41462717 Filed 2019-06-04 Fix posted WPT: css/css-sizing/{slice,clone}-intrinsic-size.html

Test cases

Each card shows two views of the same div with width: min-content:

Rendered - rendered live by your current browser. Will look correct only once the fix has shipped to your channel.
Expected - PNG captured from a locally built content_shell with the fix applied. Matches the WPT reference.

slice-intrinsic-size: `aaa aaa`

Expected min-content width = 78px (span2's left edge stays on line 1). Pre-fix Blink rendered the div at 64px (span2's left edge incorrectly pushed to line 2).

aaa aaa

content_shell render of slice testcase with the fix (width 78)

Reference: `aaa aaa`

Forces the break inside span2 with an explicit  . Always renders at width 78. The "Expected" testcase above must match this.

aaa
aaa

content_shell render of slice reference (width 78)

clone-intrinsic-size: same markup, `box-decoration-break: clone`

With clone, span2's full box decoration is duplicated on each line, so the pre-fix width lost 36px (margin+border+padding both sides). Expected = 100px, pre-fix = 64px.

aaa aaa