[CSS Grid Layout] Add parsing for grid-{start|before}
https://bugs.webkit.org/show_bug.cgi?id=110988

Reviewed by Tony Chang.

Source/WebCore:

Test: fast/css-grid-layout/grid-item-start-before-get-set.html

Refactored how we store internally grid-{row|column} to be based on grid-{before|start}.
This is required as grid-{row|column} are shorthands for resp. grid-{before|after} and grid-{start|end}
in the specification and will also be in the code. That means a lot of methods were renamed to be more
aligned with the new design.

* css/CSSComputedStyleDeclaration.cpp:
(WebCore::CSSComputedStyleDeclaration::getPropertyCSSValue):
* css/CSSParser.cpp:
(WebCore::CSSParser::parseValue):
* css/CSSProperty.cpp:
(WebCore::CSSProperty::isInheritedProperty):
* css/CSSPropertyNames.in:
* css/StyleResolver.cpp:
(WebCore::StyleResolver::applyProperty):
Added the code to parse, apply and get back the new properties. Also
some renaming after the internal naming change below.

* rendering/RenderGrid.cpp:
(WebCore::RenderGrid::maximumIndexInDirection):
(WebCore::RenderGrid::placeItemsOnGrid):
(WebCore::RenderGrid::autoPlacementMajorAxisPositionForChild):
(WebCore::RenderGrid::autoPlacementMinorAxisPositionForChild):
* rendering/style/RenderStyle.h:
* rendering/style/StyleGridItemData.cpp:
(WebCore::StyleGridItemData::StyleGridItemData):
* rendering/style/StyleGridItemData.h:
(WebCore::StyleGridItemData::operator==):
Updated the naming now that we manipulate grid-{before|start} instead of grid-{row|column}.

LayoutTests:

* fast/css-grid-layout/grid-item-column-row-get-set-expected.txt:
* fast/css-grid-layout/grid-item-column-row-get-set.html:
Extended the test to make sure that both grid-column (resp. grid-row) and grid-start (resp. grid-before) are
in sync.

* fast/css-grid-layout/grid-item-start-before-get-set-expected.txt: Added.
* fast/css-grid-layout/grid-item-start-before-get-set.html: Added
Add this test for grid-{start|before}, similar to LayoutTests/fast/css-grid-layout/grid-item-column-row-get-set.html.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144681 268f45cc-cd09-0410-ab3c-d52691b4dbfc