Fix ripples escaping tree items.

CL:1617041 changed the positioned elements in the directory tree
to allow the eject button on removable items to be positioned at
the width of the left hand pane in the FilesApp in cases where
the content in the left pane allows horizontal scrolling to
occur.

The Polymer 'paper-ripple' on the tree rows uses its ancestor
positioned element to calculate the bounds for clipping the ripple
effect. The result is that the new ancestor is the entire tree and
so the ripple escapes the bounds of the tree row.

This CL reinstates position:relative onto the tree rows which is
used by the Polymer paper-ripple element to contain the extent
of the ripple effect.

Bug: 965382
Change-Id: I47c07ef886d056a9b72dc161197e57d1bea3c551
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1623649
Commit-Queue: Alex Danilo <adanilo@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662100}
2 files changed