Move RenderLayer repainting to repaint-after-layout framework.

This CL updates the RenderLayer repainter code to be a no-op during
repaint-after-layout. The repainting of updated layers is handled in the
repaintTree method, the same as non-layer RenderObjects.

While making this change we discovered that the outline rect can not be
calculated from the repaint rect. So, we've had to add the old/new outline rects to the RenderObject so we can have the correct values.

BUG=320139
COLLABORATOR=jchaffraix@chromium.org

Review URL: https://codereview.chromium.org/160903002

git-svn-id: svn://svn.chromium.org/blink/trunk@169684 bbb929c8-8fbe-4397-9dbb-9b2b20218538