Abs-positioned objects should move with inline rel-positioned containers when the latter change width

In line layout the position of an absolute positioned object that has a fixed
offset from an inline rel-positioned container needs to move if the container changes
width. If we are positioning an abspos object inside a rel-pos container during line
layout then its container has probably changed width - so force a layout on the object
if its position depends on the edge that moves with the width.

BUG=338856

Review URL: https://codereview.chromium.org/372023002

git-svn-id: svn://svn.chromium.org/blink/trunk@179335 bbb929c8-8fbe-4397-9dbb-9b2b20218538