Removing a RenderLayer's CLM should trigger a repaint

This makes RLC::applyUpdateLayerCompositingStateChickenEggHacks
issue a repaint when a RenderLayer gains or loses a CLM.

Review URL: https://codereview.chromium.org/336493004

git-svn-id: svn://svn.chromium.org/blink/trunk@176128 bbb929c8-8fbe-4397-9dbb-9b2b20218538