Don't force repaint layer on size change

This CL reverts the patch of wkbug.com/104626 (except the layout test).
The test added in the patch still passes, proving that the patch is
unnecessary in blink.

This is part of work for crbug.com/258219 to reduce the paths of
full view repainting on viewport size change.

BUG=258219
TEST=existing test compositing/repaint/clipped-layer-size-change.html

Review URL: https://codereview.chromium.org/113283007

git-svn-id: svn://svn.chromium.org/blink/trunk@163801 bbb929c8-8fbe-4397-9dbb-9b2b20218538