Revert of Directly schedule compositing updates for <canvas> (https://codereview.chromium.org/265833007/)

Reason for revert:
Caused a number of browser_tests to fail:

NetInternalsTest.netInternals*

ASSERTION FAILED: renderBox()
../../third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp(531) : void WebCore::HTMLCanvasElement::setNeedsCompositingUpdate()

Original issue's description:
> Directly schedule compositing updates for <canvas>
> 
> Instead of using scheduleLayerUpdate() to trigger the compositing state
> change for the <canvas>, we can directly set the bits on the
> RenderLayerCompositor and our RenderLayer.
> 
> This removes several usages of scheduleLayerUpdate(), which we want to
> remove since it requires calling into setStyle() with identical styles
> and is the source of chicken and egg issues with the compositing update.
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=173232

TBR=ojan@chromium.org,senorblanco@chromium.org,esprehn@chromium.org
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/268003003

git-svn-id: svn://svn.chromium.org/blink/trunk@173268 bbb929c8-8fbe-4397-9dbb-9b2b20218538