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

This reverts commit 126d3f1d4ded9aa8809692904f9840521422474a.

Land this again with the fix for the build breakage.

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

Review URL: https://codereview.chromium.org/176843020

git-svn-id: svn://svn.chromium.org/blink/trunk@168648 bbb929c8-8fbe-4397-9dbb-9b2b20218538