Note that the syntax has just been discussed on the CSS WG.

Check the last comments on this issue before implementing them:
https://github.com/w3c/csswg-drafts/issues/595#issuecomment-262709407

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/6c74eacf0850ef3ed1c3036af6231eb89cfb782f

commit 6c74eacf0850ef3ed1c3036af6231eb89cfb782f
Author: jfernandez <jfernandez@igalia.com>
Date: Mon Mar 06 14:18:49 2017

[css-align] Implement place-content alignment shorthand

The CSS Box Alignment specification defines a new shorthand to set the
Content Alignment properties (align-content and justify-content) at the
same time.

This patch provides the implementation of the CSS parsing logic and the
required regression tests. For the time being, as it happens with the
rest of the new alignment properties, the new parsing logic is
implemented behind the CSS Grid Layout runtime flag.

The intent-to-implement-and-ship of CSS Box Alignment shorthands is:

https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/DK189tnM8l4

BUG= 668639 

Review-Url: https://codereview.chromium.org/2662573002
Cr-Commit-Position: refs/heads/master@{#454864}

[add] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/LayoutTests/fast/alignment/parse-place-content.html
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/LayoutTests/fast/alignment/resources/alignment-parsing-utils-th.js
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/LayoutTests/virtual/stable/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/LayoutTests/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/CSSProperties.json5
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/StylePropertySerializer.cpp
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/StylePropertySerializer.h
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.h
[modify] https://crrev.com/6c74eacf0850ef3ed1c3036af6231eb89cfb782f/third_party/WebKit/Source/core/frame/UseCounter.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4028e23294216bb50e416b43ca9e2a30b95d164b

commit 4028e23294216bb50e416b43ca9e2a30b95d164b
Author: jfernandez <jfernandez@igalia.com>
Date: Wed Apr 05 07:33:35 2017

[css-align] Implement place-items alignment shorthand

The CSS Box Alignment specification defines a new shorthand to set the
Content Alignment properties (align-items and justify-items) at the
same time.

This patch provides the implementation of the CSS parsing logic and the
required regression tests. For the time being, as it happens with the
rest of the new alignment properties, the new parsing logic is
implemented behind the CSS Grid Layout runtime flag.

The intent-to-implement-and-ship of CSS Box Alignment shorthands is:

https://groups.google.com/a/chromium.org/forum/#!topic/Blink-dev/qCfsZJhGtOQ

BUG= 668639 

Review-Url: https://codereview.chromium.org/2737843003
Cr-Commit-Position: refs/heads/master@{#462003}

[add] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/LayoutTests/fast/alignment/parse-place-items.html
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/LayoutTests/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/CSSProperties.json5
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/StylePropertySerializer.cpp
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/StylePropertySerializer.h
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.h
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/properties/CSSPropertyAlignmentUtils.cpp
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/css/properties/CSSPropertyAlignmentUtils.h
[modify] https://crrev.com/4028e23294216bb50e416b43ca9e2a30b95d164b/third_party/WebKit/Source/core/frame/UseCounter.cpp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d332296ceffaf87939123159cb58d12dea283c27

commit d332296ceffaf87939123159cb58d12dea283c27
Author: jfernandez <jfernandez@igalia.com>
Date: Fri Apr 07 12:10:01 2017

[css-align] Implement place-self alignment shorthand

The CSS Box Alignment specification defines a new shorthand to set the
Self Alignment properties (align-self and justify-self) at the
same time.

This patch provides the implementation of the CSS parsing logic and the
required regression tests. For the time being, as it happens with the
rest of the new alignment properties, the new parsing logic is
implemented behind the CSS Grid Layout runtime flag.

The intent-to-implement-and-ship of CSS Box Alignment shorthands is:

https://groups.google.com/a/chromium.org/forum/#!topic/Blink-dev/qCfsZJhGtOQ

BUG= 668639 

Review-Url: https://codereview.chromium.org/2804623002
Cr-Commit-Position: refs/heads/master@{#462842}

[add] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/LayoutTests/fast/alignment/parse-place-self.html
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/LayoutTests/virtual/stable/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/LayoutTests/webexposed/css-properties-as-js-properties-expected.txt
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/css/CSSProperties.json5
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/css/ComputedStyleCSSValueMapping.cpp
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/css/StylePropertySerializer.cpp
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.cpp
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/css/parser/CSSPropertyParser.h
[modify] https://crrev.com/d332296ceffaf87939123159cb58d12dea283c27/third_party/WebKit/Source/core/frame/UseCounter.cpp

We can mark this bug as FIXED.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cb4e6a04496ddfff77976950c620fb3448abcd96

commit cb4e6a04496ddfff77976950c620fb3448abcd96
Author: jfernandez <jfernandez@igalia.com>
Date: Thu May 11 08:03:17 2017

[css-align] Fixed errors place-self parsing tests

The place-self parsing regression tests are incorrect as they were
using place-items property instead.

BUG= 668639 

Review-Url: https://codereview.chromium.org/2874773003
Cr-Commit-Position: refs/heads/master@{#470867}

[modify] https://crrev.com/cb4e6a04496ddfff77976950c620fb3448abcd96/third_party/WebKit/LayoutTests/fast/alignment/parse-place-self.html