Unreviewed gardening. Marked http/tests/css/css-image-loading.html as SLOW.

* platform/chromium/TestExpectations:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142431 268f45cc-cd09-0410-ab3c-d52691b4dbfc
Unreviewed gardening. Rebaselined an image.

* platform/chromium-mac/fast/backgrounds/repeat/negative-offset-repeat-transformed-expected.png:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142432 268f45cc-cd09-0410-ab3c-d52691b4dbfc