Pass LayerPaintingInfo to clipToRect

Every callsite explicitly passed the root layer and paint dirty rect,
breaking them out of LayerPaintingInfo. This just passes in
LayerPaintingInfo. This is only a simple refactoring. No behavior change.

Review URL: https://codereview.chromium.org/173043002

git-svn-id: svn://svn.chromium.org/blink/trunk@167643 bbb929c8-8fbe-4397-9dbb-9b2b20218538