Unreviewed gardening

css3/filters/composited-during-animation-layertree.html is flaky on all platforms.

TBR=
BUG=

Review URL: https://codereview.chromium.org/19699012

git-svn-id: svn://svn.chromium.org/blink/trunk@154687 bbb929c8-8fbe-4397-9dbb-9b2b20218538