Layout Test fast/dom/StyleSheet/gc-declaration-parent-rule.html is failing

BUG=370906
TBR=wibling@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/274453006

git-svn-id: svn://svn.chromium.org/blink/trunk@173534 bbb929c8-8fbe-4397-9dbb-9b2b20218538