Get rid of scheduleSVGFilterLayerUpdateHack call for plugins.

We need to store a bit on the RenderStyle as to whether it needs
to be accelerated due to the plugin having a layer so that when
we recalc style on it, we actually get a different style and
call setStyle. This is needed so styleChanged gets called
and we get a NormalLayer RenderLayer.

This is better than the current hack because we'd like it to
be an invariant that setStyle is only called when the style
actually changed.

Revert "Psuedo revert "s/scheduleLayerUpdate/setNeedsCompositingUpdate in setWebLayer.""

This reverts commit 2c54e3cf4c74a20c2319bc3bae26904fbb462330.

Review URL: https://codereview.chromium.org/328553004

git-svn-id: svn://svn.chromium.org/blink/trunk@175914 bbb929c8-8fbe-4397-9dbb-9b2b20218538