Add support for 'order' on grid items

Add support for 'order' on grid items

The property is used to modify painting order and the order in which
we consider grid items for the auto-flow algorithm.

The code is build on the existing OrderIterator and matches what
flexbox does. Also to avoid adding an extra child walk, refactored
the explicit grid initialization so that we do also initialize the
OrderIterator's Vector. This refactoring saves a child walk as we
now compute both explicit grid's sizes in a single child walk.

BUG=257078
TESTS=fast/css-grid-layout/grid-item-order-auto-flow-resolution.html
      fast/css-grid-layout/grid-item-order-paint-order-expected.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=153536

[Julien - ping for review, 2013-07-03 20:06:26]

None of the trybot failures are grid related.

[ojan, 2013-07-03 20:21:57]

lgtm

https://codereview.chromium.org/18516007/diff/1/Source/core/rendering/OrderIt...
File Source/core/rendering/OrderIterator.h (right):

https://codereview.chromium.org/18516007/diff/1/Source/core/rendering/OrderIt...
Source/core/rendering/OrderIterator.h:47: OrderIterator(const RenderGrid*);
Lets just have it take a const RenderBox* instead of having multiple
constructors. In theory, we'll eventually support order on other RenderBox types
as well (e.g. display:block).

[Julien - ping for review, 2013-07-03 21:38:16]

https://codereview.chromium.org/18516007/diff/1/Source/core/rendering/OrderIt...
File Source/core/rendering/OrderIterator.h (right):

https://codereview.chromium.org/18516007/diff/1/Source/core/rendering/OrderIt...
Source/core/rendering/OrderIterator.h:47: OrderIterator(const RenderGrid*);
On 2013/07/03 20:21:57, ojan wrote:
> Lets just have it take a const RenderBox* instead of having multiple
> constructors. In theory, we'll eventually support order on other RenderBox
types
> as well (e.g. display:block).

Done.

[commit-bot: I haz the power, 2013-07-03 21:39:01]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jchaffraix@chromium.org/18516007/6001

[commit-bot: I haz the power, 2013-07-03 23:40:14]

Change committed as 153536