Revert "Revert everything related to avoiding repaints when scrolling composited layers"

This reverts commit edb8ee49dd781b0e8fb4b2f0e69df43cbf8d66a5, which reverted all
CL's related to the avoidance of repaint when scrolling composited layers.

>    This change reverts the following changes
>    
>    1) "Avoid unnecessary repaints when scrolling composited layers"
>      commit cb83ea82bdddf046ac06fe9b3c9e98c39b132c0f.
>      Review URL: https://codereview.chromium.org/27239004
>    
>    2) "Be sure to repaint if we're scrolling a marquee."
>      commit 6381190bee369232e502aa3bbfc7ce9700625348
>      Review URL: https://codereview.chromium.org/50493016
>    
>    3) "Only skip repaints for layers whose bookkeeping is up to date"
>      commit 42b329b685391994ee5ae5a06b614d03effd6a97.
>      Review URL: https://codereview.chromium.org/79263002
>    
>    BUG=319655
>    R=shawnsingh@chromium.org
>    
>    Review URL: https://codereview.chromium.org/78233006

Review URL: https://codereview.chromium.org/85383007

git-svn-id: svn://svn.chromium.org/blink/trunk@162666 bbb929c8-8fbe-4397-9dbb-9b2b20218538