Make LayoutDelta do nothing when RepaintAfterLayout is active.

This CL, essentially, removes the LayoutDelta code when we have repaint-after-layout
enabled. When repaint-after-layout is enabled and the flag removed we can rip out
the LayoutDelta code at the same time.

This CL lets us verify that everything continues to work correctly without LayoutDelta.

BUG=310397

Review URL: https://codereview.chromium.org/144553004

git-svn-id: svn://svn.chromium.org/blink/trunk@165683 bbb929c8-8fbe-4397-9dbb-9b2b20218538