[Effen] Move 'flex' out of CSS also. (mark II)

[Effen] Move 'flex' out of CSS also. (mark II)

This introduces a new kind of ContentNode similar to Style but which
instead of changing the styles that apply to the node, provides new
settings to apply to the "parentData" structure.

R=eseidel@chromium.org

Committed: https://chromium.googlesource.com/external/mojo/+/31dde9c30bf5b61c2df7656d69c5174a887ccb74

[eseidel, 2015-05-12 17:31:58]

eseidel@chromium.org changed reviewers:
+ eseidel@chromium.org

[eseidel, 2015-05-12 17:31:59]

lgtm

https://codereview.chromium.org/1122413006/diff/1/sky/framework/layout.dart
File sky/framework/layout.dart (right):

https://codereview.chromium.org/1122413006/diff/1/sky/framework/layout.dart#n...
sky/framework/layout.dart:272: if (newStyle == null)
dart doesn't have a fancy pattern for this?

_inlineStyles = newStyle if (newStyle != null) else '';

or
_inlineStyles ?= newStyle;

or similar?

https://codereview.chromium.org/1122413006/diff/1/sky/framework/layout.dart#n...
sky/framework/layout.dart:280: if ((_inlineStyles != '') &&
(_additionalStylesFromParent != ''))
style = [inlineStyles, additionalStylesFromParent].join(';').strip(';')
would work too?

https://codereview.chromium.org/1122413006/diff/1/sky/tests/framework/basic-e...
File sky/tests/framework/basic-expected.txt (right):

https://codereview.chromium.org/1122413006/diff/1/sky/tests/framework/basic-e...
sky/tests/framework/basic-expected.txt:4: <img debug="Instance of 'Image'"
src="resources/united.jpg" class="" style=""></img>
Why?

[Hixie, 2015-05-12 17:40:48]

Committed patchset #2 (id:20001) manually as
31dde9c30bf5b61c2df7656d69c5174a887ccb74 (presubmit successful).