Revert of Put the squashing layer underneath the ancestor clipping layer if present.

Revert of Put the squashing layer underneath the ancestor clipping layer if present. (https://codereview.chromium.org/215823002/)

Reason for revert:
This appears to have unexpected effects on rendering. Bits of gmail are missing for example.

Original issue's description:
> Put the squashing layer underneath the ancestor clipping layer if present.
> 
> Previously, this was the case for m_graphicsLayer but not m_squashingLayer.
> Since they now are guaranteed to have the same clipping ancestor, this is both
> safe and correct.
> 
> BUG=336563
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170348

TBR=hartmanng@chromium.org,chrishtr@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=336563
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=170413

[Ian Vollick, 2014-03-29 09:35:13]

Created Revert of Put the squashing layer underneath the ancestor clipping layer
if present.

[commit-bot: I haz the power, 2014-03-29 09:35:19]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/vollick@chromium.org/218313002/1

[commit-bot: I haz the power, 2014-03-29 09:35:36]

Change committed as 170413

[chrishtr, 2014-03-31 17:34:30]

FYI I'm not able to repro the break described here so far on Linux Aura.

[chrishtr, 2014-04-01 03:05:03]

A revert of this CL has been created in
https://codereview.chromium.org/219223008/ by chrishtr@chromium.org.

The reason for reverting is: The breakage is only with
--enable-universal-accelerated-overflow-scroll true. Since that feature is not
launched and not tied to squashing, going to re-lad the original CL..