Mark the layer for which updateLayerPosition returned true for paint invalidation

Previously, we were just doing that for child layers. This meant that sometimes a layer would move after layout, but we would not invalidate its old and new paint positions.

In particular, this happened with the added test, in which a leaf RenderLayer (backing a div element) moved to the left after its sibling with inline-block layout was removed. The RenderLayer that moved did not participate in layout (since it itself did not get laid out, but was moved by updateLayerPosition since its position changed as a result of external forces.

BUG=384945

Review URL: https://codereview.chromium.org/352193002

git-svn-id: svn://svn.chromium.org/blink/trunk@176953 bbb929c8-8fbe-4397-9dbb-9b2b20218538