[css-align] Initial value of align-content should be 'stretch'.

[css-align] Initial value of align-content should be 'stretch'.

We only allow the new CSS Box Alignment syntax when the Grid Layout
feature is enabled. Due to flexbox backward compatibility we have
implemented a different code path for the style initial/default values
assignment. However, we have incorrectly resolved both align-content
and justify-content to 'flex-start' when grid layout is disabled.

This patch changes the approach, so we set 'normal' (the value specified
by the new syntax) for both properties, but using the values defined in
the old syntax (Flexbox specification) at computed style resolution.

Since 'stretch' is the default value for the align-content property, this
issue implies that any flexbox line with an undefined height will be
laid out incorrectly, if not explicitly set via CSS, because flex items
can't use the available height, even though they use 'stretch' for their
'align-self' properties.

BUG=647694
Review-Url: https://codereview.chromium.org/2348273002
Cr-Commit-Position: refs/heads/master@{#419737}
(cherry picked from commit eeac3e6a187e362d796fa01489927e773be705ac)

Committed: https://chromium.googlesource.com/chromium/src/+/72308707baae9aac0bea97387c1b4426bd378f51

[cbiesinger, 2016-09-22 14:57:30]

Description was changed from

==========
[css-align] Initial value of align-content should be 'stretch'.

We only allow the new CSS Box Alignment syntax when the Grid Layout
feature is enabled. Due to flexbox backward compatibility we have
implemented a different code path for the style initial/default values
assignment. However, we have incorrectly resolved both align-content
and justify-content to 'flex-start' when grid layout is disabled.

This patch changes the approach, so we set 'normal' (the value specified
by the new syntax) for both properties, but using the values defined in
the old syntax (Flexbox specification) at computed style resolution.

Since 'stretch' is the default value for the align-content property, this
issue implies that any flexbox line with an undefined height will be
laid out incorrectly, if not explicitly set via CSS, because flex items
can't use the available height, even though they use 'stretch' for their
'align-self' properties.

BUG=647694

Review-Url: https://codereview.chromium.org/2348273002
Cr-Commit-Position: refs/heads/master@{#419737}
(cherry picked from commit eeac3e6a187e362d796fa01489927e773be705ac)
==========

to

==========
[css-align] Initial value of align-content should be 'stretch'.

We only allow the new CSS Box Alignment syntax when the Grid Layout
feature is enabled. Due to flexbox backward compatibility we have
implemented a different code path for the style initial/default values
assignment. However, we have incorrectly resolved both align-content
and justify-content to 'flex-start' when grid layout is disabled.

This patch changes the approach, so we set 'normal' (the value specified
by the new syntax) for both properties, but using the values defined in
the old syntax (Flexbox specification) at computed style resolution.

Since 'stretch' is the default value for the align-content property, this
issue implies that any flexbox line with an undefined height will be
laid out incorrectly, if not explicitly set via CSS, because flex items
can't use the available height, even though they use 'stretch' for their
'align-self' properties.

BUG=647694

Review-Url: https://codereview.chromium.org/2348273002
Cr-Commit-Position: refs/heads/master@{#419737}
(cherry picked from commit eeac3e6a187e362d796fa01489927e773be705ac)

Committed:
https://chromium.googlesource.com/chromium/src/+/72308707baae9aac0bea97387c1b...
==========

[cbiesinger, 2016-09-22 14:57:31]

Committed patchset #1 (id:1) manually as
72308707baae9aac0bea97387c1b4426bd378f51.