Revert 178746

Revert 178746
> Avoid going through WebWidget::composite to composite a RenderWidget
> 
> When a content::RenderWidget is using accelerated compositing, the compositing
> is driven either by a WebLayerTreeView owned by the RenderWidget or a PepperWidget
> if the RenderWidget is actually a RenderWidgetFullscreenPepper. Neither case
> involves WebKit, so this avoids calling WebWidget::composite in favor of directly
> calling in to the appropriate compositing system.
> 
> BUG=
> 
> 
> Review URL: https://chromiumcodereview.appspot.com/11787006

TBR=jamesr@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=179371