Add some repaintAfterLayout updates to the SVG code.

There are a couple places in the SVG code where we issue repaints during layout.
This CL wraps those calls appropriatly when we are doing repaintAfterLayout.

BUG=310398

Review URL: https://codereview.chromium.org/109073006

git-svn-id: svn://svn.chromium.org/blink/trunk@163888 bbb929c8-8fbe-4397-9dbb-9b2b20218538