The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/adeae69afea91b503de336275bad316a43080ee4

commit adeae69afea91b503de336275bad316a43080ee4
Author: ericwilligers <ericwilligers@chromium.org>
Date: Wed Jun 14 00:46:31 2017

CSS: distance and rotate optional in 'offset'

offset-distance and offset-rotate are optional in the offset shorthand.
If both are present, they may appear in either order.

If the CSSOffsetPositionAnchor feature flag is enabled, offset-position
and offset-anchor are also supported in the shorthand.

Grammar from spec:
https://drafts.fxtf.org/motion-1/#offset-shorthand
[ <offset-position>?
  [ <offset-path> [ <offset-distance> || <offset-rotate> ]? ]?
]!
[ / <offset-anchor> ]?

Bug: 654664
Change-Id: Ibce18386f864b9e35a5c0ef4b9ae444512067fba
Reviewed-on: https://chromium-review.googlesource.com/526840
Reviewed-by: Rune Lillesveen <rune@opera.com>
Commit-Queue: Eric Willigers <ericwilligers@chromium.org>
Cr-Commit-Position: refs/heads/master@{#479230}
[delete] https://crrev.com/75af3a8ba9bd8724e83d99db0113bc8836b472ae/third_party/WebKit/LayoutTests/css-parser/offset-parsing.html
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/LayoutTests/external/wpt/css/motion-1/parsing/offset-parsing-invalid.html
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/LayoutTests/external/wpt/css/motion-1/parsing/offset-parsing-valid.html
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/build/scripts/templates/StylePropertyShorthand.cpp.tmpl
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/CSSProperties.json5
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.h
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/StylePropertySerializer.cpp
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/StylePropertySerializer.h
[modify] https://crrev.com/adeae69afea91b503de336275bad316a43080ee4/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot