Bug 124345

There are some FIXME's in the code mentioning that we aren't considering the margins in the layouting of the grid items. Apart from that margins should be also considered when computing the grid's intrinsic size. Fixing this would involve merging these two changes from Blink: Positioning should account for the grid items' margins This change just adds the margin before / start to the grid items' positions. In order to get consistent behavior, we now have to call findChildLogicalPosition after layout (that's where we compute the margins). Also removed some FIXMEs that were handled in the code. Review URL: https://chromiumcodereview.appspot.com/23463036 and RenderGrid should include grid items' margins in its intrinsic size To match flexbox and the author's intent, the grid element's intrinsic logical widths should account for the fixed margins on any grid items'. The change is straightforward and moves the code from RenderFlexibleBox to RenderBlock for easy sharing. Review URL: https://chromiumcodereview.appspot.com/24031007