Revert 179538 "Untangle NeedsFullPaintInvalidationInBacking from..."

Suspected of causing multiple crashes on the WebKit bots.

> Untangle NeedsFullPaintInvalidationInBacking from updateLayerPositionsAfterLayout
> 
> There's no reason to pass NeedsFullPaintInvalidationInBacking into
> updateLayerPositionsAfterLayout. We can just repaint all the composited layers
> using RenderLayerCompositor::fullyInvalidatePaint(), which does a separate
> walk of the RenderLayer tree.
> 
> I've also changed RenderLayerCompositor::fullyInvalidatePaint() to walk in tree
> order instead of in z-order. There's no reason to walk in z-order and walking in
> tree order is faster.
> 
> R=esprehn@chromium.org
> BUG=382548
> 
> Review URL: https://codereview.chromium.org/438173002

TBR=abarth@chromium.org

Review URL: https://codereview.chromium.org/444813003

git-svn-id: svn://svn.chromium.org/blink/trunk@179546 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix for filter backing store size cap.

Use the device scale when capping the upper size of the filter backing
store, not the world-space size.

Also add a comment to remove this once all platforms use impl-side
painting.

BUG=400445

Review URL: https://codereview.chromium.org/446593003

git-svn-id: svn://svn.chromium.org/blink/trunk@179547 bbb929c8-8fbe-4397-9dbb-9b2b20218538