Fix repainting of line layout when repaint-after-layout is enabled.

The CL https://src.chromium.org/viewvc/blink?view=rev&revision=165800 changed
how the line layouts re-repainted. This CL adds in the needed updates for the
new code to work with repaint-after-layout.

BUG=336253

Review URL: https://codereview.chromium.org/148333008

git-svn-id: svn://svn.chromium.org/blink/trunk@165974 bbb929c8-8fbe-4397-9dbb-9b2b20218538