Revert of Move all RefPtr's to CSSValue to oilpan transition types

Revert of Move all RefPtr's to CSSValue to oilpan transition types, except for the one in CSSCursorImageValue. (https://codereview.chromium.org/184313004/)

Reason for revert:
It seems to break some of our layout tests.

Original issue's description:
> Move all RefPtr's to CSSValue to oilpan transition types, except for the one in CSSCursorImageValue.
> 
> This change gets rid of all but one RefPtr to CSSValue. I have introduced a few persistents core/animation/..., core/css/StylePropertySet, and ElementStyleResources. I plan to attack the one in CSSCursorImageValue subsequently, and then change CSSValue from RefCountedGarbageCollected to GarbageCollectedFinalized.
> 
> R=ager@chromium.org, erik.corry@gmail.com, haraken@chromium.org, oilpan-reviews@chromium.org, tkent@chromium.org, vegorov@chromium.org, zerny@chromium.org
> BUG=341815
> NOTRY=true
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168466

TBR=ager@chromium.org,erik.corry@gmail.com,haraken@chromium.org,oilpan-reviews@chromium.org,tkent@chromium.org,vegorov@chromium.org,zerny@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=341815
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=168492

[wibling-chromium, 2014-03-05 15:52:57]

Created Revert of Move all RefPtr's to CSSValue to oilpan transition types,
except for the one in CSSCursorImageValue.

[haraken, 2014-03-05 15:54:04]

LGTM

[commit-bot: I haz the power, 2014-03-05 15:54:50]

Change committed as 168492

[zerny-chromium, 2014-03-05 16:57:09]

lgtm